3.1 The Derivative and the Tangent Line Problem Apply ... 03 Homework Complete Solutions V2 Part 1:...
Transcript of 3.1 The Derivative and the Tangent Line Problem Apply ... 03 Homework Complete Solutions V2 Part 1:...
Ch 03 Homework Complete Solutions V2 Part 1: S. Stirling Name _________________________________
Calculus: Early Transcendental Functions, 4e Larson
S. Stirling 2016 - 2017 Page 1 of 41
3.1 The Derivative and the Tangent Line Problem
Apply & Practice 3.1 Set 1: P 123-124
#1-4 Estimating slope & concept.
#6, 8, 9 slope @ point use diff. quotient if necessary.
The slope as x 3
should get less
steep. Draw secant
lines if needed.
Slopes are
estimated by
using the grids to
approximate the
slopes.
Draw secant line
and tangent line if
needed.
Ch 03 Homework Complete Solutions V2 Part 1: S. Stirling Name _________________________________
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S. Stirling 2016 - 2017 Page 2 of 41
8. Find slope of the tangent line to 2( ) 5g x x
at 2,1
9. 2( ) 3f t t t at 0,0
You MUST use0
( ) ( )( ) lim
x
f x x f xf x
x
even if you know the slope!
So slope = 3/2 at any point.
Note: 2x and 22 5 2 1g
Numerator:
3 3 2 3 2 3x x x x
Gives 0/0, so you
would have to use
knowledge of the
graph here.
0
0
0
1 1 19 92 2 2lim
12lim
1 1lim
2 2
x
x
x
x x x
x
x
x
Apply & Practice 3.1 Set 2: P 124 & 126 YOU MUST USE
THE FORM THEY SPECIFY!
#12-20 (even) Use diff. quotient!
#71, 74, 76 Use alternate form!
#30 VIP equation of the tangent
line.
Ch 03 Homework Complete Solutions V2 Part 1: S. Stirling Name _________________________________
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S. Stirling 2016 - 2017 Page 3 of 41
Note: 22 2 1 3f
You MUST use( ) ( )
( ) limx a
f x f af a
x a
!
Note: 31 1 2 1 3f
Note: 1 1 3
3 3
x
x x
and multiplied by the reciprocal
Expanding Shortcuts are helpful here:
3 3 2 2 33 3a b a a b ab b and
2 2 22a b a ab b
Use Rational Root Thm. and
synthetic division to factor.
1 1 0 2 3
1 1 3
1 1 3 0
Ch 03 Homework Complete Solutions V2 Part 1: S. Stirling Name _________________________________
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S. Stirling 2016 - 2017 Page 4 of 41
30. Find the equation of the tangent line to the curve, ( ) 1f x x , at 5, 2 . (b) graph and (c) confirm
on calculator.
The equation of the tangent line:
1
5 24
y x
Again, AP loves this form! Don’t
change it to slope-intercept.
(c) nDeriv(√(X – 1), X, 5) returns .25 or 5X
dX -1
dx
And to get (b), do Y1 = √(X – 1) and Y2 = .25(X – 5)+2
Ch 03 Homework Complete Solutions V2 Part 1: S. Stirling Name _________________________________
Calculus: Early Transcendental Functions, 4e Larson
S. Stirling 2016 - 2017 Page 5 of 41
Apply & Practice 3.1 Set 3: P 124-125
#37-40, 43-48 Given f find graph f ʹ
#49-52 writing
#53-56 sketch
#59 concept
#63, 68 make good sketches of what you see!
Constant slope horizontal line.
( )f x x ( ) 1f x
Negative slope when x < 0
Zero slope when x = 0
Positive slope when x > 0
2( )f x x ( ) 2f x x
At x = 0, slope
Slope decreases as x
Always a positive slope
( )f x x ( ) 1 2f x x
Slope constant –1 from left.
Slope constant 1 from right.
At x = 0, slope DNE.
Ch 03 Homework Complete Solutions V2 Part 1: S. Stirling Name _________________________________
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S. Stirling 2016 - 2017 Page 6 of 41
49. Compare to the difference quotient
5 3(1 ) 2 ( ) ( )x f x x f x
x x
( ) 5 3(1 )f x x x so 1x
guess ( ) 5 3f x x
check (1) 5 3(1) 2f or ( ) 2f x
So ( ) 5 3f x x and 1c
Also…
1
2
x
y or as long as the
base is between 0 and 1.
(Exponential decay.)
Or 1
yx
…
Or Any function that is
always decreasing.
Also…
2xy or as long as the
base is greater than 1.
(Exponential growth.)
Or lny x or any log
Or y x
Or Any function that is
always increasing.
Great AP problems!
50. Compare to the difference quotient
3
2 8 ( ) ( )x f x x f x
x x
3( ) ( 2 )f x x x so 2x
guess 3( )f x x
check 3( 2) ( 2)f or ( ) 8f x
So 3( )f x x and 2c
51. Compare to the alt. definition 2 36 ( ) ( )
6
x f x f c
x x c
so 6c and 2( )f x x
check 2(6) (6)f or
( ) 36f c
So 2( )f x x and 6c
52. Compare to the alt. definition
( ) ( ) 2 2 9
9
f x f c x
x c x
so 9c and ( ) 2f x x
check (9) 2 9f or
( ) 2 9f c
So ( ) 2f x x and 9c
Ch 03 Homework Complete Solutions V2 Part 1: S. Stirling Name _________________________________
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S. Stirling 2016 - 2017 Page 7 of 41
On , 2 , f increases quickly then levels off, slope large positive to
small positive.
At x = –2, the slope, f , is zero. Likewise at x = 2.
On 2,2 , f decreases slowly to quickly to slowly. Slope slightly negative to really negative to slightly negative.
On 2, , f increases slowly to quickly. Slope small positive to large positive.
Y1 = X^3/4 – 3X
Y2 = nDeriv(Y1, X, X)
Zeros of Y1:
X = –2, X = 2
On [4, 6] , g’ positive so g is increasing
You don’t have any values for g, so the function can be
any vertical translation (shift) of g.
Graph of the derivative!
Positive slopes g increasing
Negative slopes g decreasing
Almost the derivative!
Secant slope for a small x .
Ch 03 Homework Complete Solutions V2 Part 1: S. Stirling Name _________________________________
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S. Stirling 2016 - 2017 Page 8 of 41
Apply & Practice 3.1 Set 4: P 124
Alt. form of derivative
#75, 78, 80
#81-86 Differentiable? from graphs
#91, 92, 94, 96 Differentiable? analytically
#100-102 T or F
4x , ( 4)
( ) 1( 4)
xf x
x
4x , ( 4)
( ) 1( 4)
xf x
x
Also, use the graph of the absolute
value shifted right 4.
Think about the graph and get
numerator to be a constant
1x x x
x x x x x
,
0x , 1( )0
g x
0x , 1( )0
g x
x
y
x
y
13
3 23 3 33
3 1lim lim
33x x
x
xx
3x , 1( )0
f x
Think about the graph too!
Or infinite discontinuity, vertical asymptote.
Or infinite discontinuities, vertical asymptotes.
Definition:
, 0
, 0
u uu
u u
Ch 03 Homework Complete Solutions V2 Part 1: S. Stirling Name _________________________________
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S. Stirling 2016 - 2017 Page 9 of 41
Note: (1) 1f and 1 1
lim lim 1 (1)x x
x x f
So f continuous.
Always test for continuity first, because if it’s not continuous, it’s not differentiable.
Limit does not exist at x = 0, jump.
2
1 1
( ) (1) 1 0lim lim
1 1x x
f x f x
x x
2 2
21
1 1lim
1 1x
x x
x x
Makes the numerator a perfect square!
2
2 21 1
1 1 1lim lim
1 1 1 1 1x x
x x x
x x x x
21
1lim
1x
x
x
Now direct sub.
2
1 1 #
01 1
(A vertical tangent.)
The limit from the right does not exist since f is defined for x > 1.
Therefore, f is not differentiable at x = 1.
1x , ( 1)
( ) 1( 1)
xf x
x
1x , ( 1)
( ) 1( 1)
xf x
x
Also, use the graph of the absolute
value shifted right 1.
Definition:
, 0
, 0
u uu
u u
Also, use the graph. Semi-circle with a radius of 1.
Ch 03 Homework Complete Solutions V2 Part 1: S. Stirling Name _________________________________
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S. Stirling 2016 - 2017 Page 10 of 41
101. False. If the derivative from the left of a point
does not equal the derivative from the right of a
point, then the derivative does not exist at that
point. For example, if ( )f x x , then the
derivative from the left at x = 0 is –1 and the
derivative from the right at x = 0 is 1. At x = 0,
the derivative does not exist.
102. True. Differentiability implies continuity.
Check continuity first!
(2) 2(2) 2f
2lim 2 2(2) 2x
x
2
1lim ( ) 2 1 2
2xf x
So 2
(2) lim ( ) 2x
f f x
.
Ch 03 Homework Complete Solutions V2 Part 1: S. Stirling Name _________________________________
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S. Stirling 2016 - 2017 Page 11 of 41
3.2 Basic Differentiation Rules and Rates of Change
Apply & Practice 3.2 Set 1: P 136
#1-2 From graph, est. & find slope
#3-24 (mult. of 3), #7 derive
#27-30 derive
#33, 36, 38 find slope
#40-52 (even)
Ch 03 Homework Complete Solutions V2 Part 1: S. Stirling Name _________________________________
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S. Stirling 2016 - 2017 Page 12 of 41
Y1 = –.5+(7/5)X^3
nDeriv(Y1, X, 0) or 1
0X
dY
dX
Y1 = 2+3cos (X)
nDeriv(Y1, X, π) or 1
X
dY
dX
Y1 = – 4e^(X)
nDeriv(Y1, X, 1) or
1
1X
dY
dX
CAUTION! You do not have a product or quotient
rule (yet) so remember to rewrite functions in a form
that you can work with!
Ch 03 Homework Complete Solutions V2 Part 1: S. Stirling Name _________________________________
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S. Stirling 2016 - 2017 Page 13 of 41
Apply & Practice 3.2 Set 2: P 136-138
#53, 56 equation of tang. line
#57, 58, 59, 61 horiz. tang.?
#63, 66 tang. lines
#75 show no horiz. tangents
#67-72 conceptual
#83-88 conceptual T or F
Tangent Line:
5( 1) 2y x AP
or 5 3y x
For AP → 1 1
12 2
y e t e
Hint: Horizontal tangents happen when the derivative
(the slope) of the tangent line is zero. So, find the
derivative, set it equal to zero, and solve!
For x = 0, 4 2(0) 8(0) 2 2y
For x = 2, 4 2(2) 8(2) 2 14y
For x = –2, 4 2( 2) 8( 2) 2 14y
Remember 2
1yx
would have a
horizontal asymptote at y = 0 and the
slope of this function never reaches zero.
For x = , sin( )y
To find the matching
y-value when x = ln 4, ln 44(ln 4)
4 ln 4 4
y e
Y1 = X^4 – X
Y2 = -5X – 3
nDeriv(Y1, X, -1)
or 1
1X
dY
dX
You should get –5!
You need point notation!
You may use your calculator
to find function values.
The numerator ≠ 0,
so the derivative ≠ 0.
Ch 03 Homework Complete Solutions V2 Part 1: S. Stirling Name _________________________________
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S. Stirling 2016 - 2017 Page 14 of 41
Hints: If the line is tangent to the function:
They share a point in common → equate the functions.
The slope of the function at that point = the slope of the tangent
line → equate the derivatives (slopes =).
Gives two equations with two unknowns → solve the system.
Use the substitution or elimination methods.
Analytically:
OR Since 1 cos 1x
3 1 3 cos 3 1x
2 ( ) 4f x and therefore ( ) 0f x .
2 3 4 2k 2 3 4 10k
2 4 4k
The easy way: Solve for k, then substitute into
the other equation.
2 4k x now substitute into 2 4 9x kx x
2
2 2
2
2 4 4 9
2 4 4 9
9
3
x x x x
x x x x
x
x
So when 3x
2 3 4 2k
So when 3x
2 3 4 10k
If you don’t think ahead!! The hard way!! UGH: Solve for x,
then substitute into the other equation. THE HARD WAY is
22
kx now substitute into 2 4 9x kx x
2
2 2
2
2
2 2 4 2 92 2 2
1 12 4 2 2 8 9
4 2
12 5 0
4
8 20 0
10 2 0
k k kk
k k k k k
k k
k k
k k
So 10k or 2k
x
y
Show that f x cannot = 0!
Ch 03 Homework Complete Solutions V2 Part 1: S. Stirling Name _________________________________
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S. Stirling 2016 - 2017 Page 15 of 41
Note how the write that the derivative is positive,
0f or ( ) 0f x . Practice this!
Think: 0f → “The function is increasing”
“rate of change (slope) is decreasing.” →
f goes from steep to less steep.
g(x) is f(x) translated up 6 units. So the slopes
of the tangent lines at each x-value would be
the same.
g(x) is f(x) stretched up by a factor of 5 and
reflected over the x-axis. So the slopes of the
tangent lines would be opposites and 5 times
steeper.
Greatest?
positive >
negative.
(c) There is a tangent line
parallel to the secant line.
Ch 03 Homework Complete Solutions V2 Part 1: S. Stirling Name _________________________________
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S. Stirling 2016 - 2017 Page 16 of 41
Note how they generalize this. It’s
actually easy to generate.
Other answers for the criteria are
possible for #71 & 72.
Really great problems!
Ch 03 Homework Complete Solutions V2 Part 1: S. Stirling Name _________________________________
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S. Stirling 2016 - 2017 Page 17 of 41
Apply & Practice 3.2 Set 3: P 138-139 #81 linear approximation #90, 91 avg. velocity vs. instant. rate #93, 96 falling objects
#97-100 graphs of position and velocity (watch units! Velocity in mph.)
#102, 103, 104, 107
#111, 113
You could now finish the activity sheet we started in Chapter 2!
Important point on linear approximations: The
more curved the function is, the less accurate the
linear approximation will be.
Ch 03 Homework Complete Solutions V2 Part 1: S. Stirling Name _________________________________
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10 cos cos 0 13 3 2
03 3 3
f f
= 31 0.47752
Compare: 0.886 0.478 0
Conclusion: The average rate of change is
between the instantaneous rates of change at the
endpoints. Check out the graphs to confirm.
Note: “average rate of change” ≠ “the average of
the instantaneous rates of change”.
1 4.7182.718 2.859
2
0 sin 0 0f
3sin 0.866
3 3 2f
1 2 4.718g e
Compare: 1 2.718 4.718
“dropped” so 0 0v
“hit the water” when ( ) 0s t
Ch 03 Homework Complete Solutions V2 Part 1: S. Stirling Name _________________________________
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97.
When sketching, you must label your axes (and
not x and y) and establish the scale on each.
2 mi 60 min mi30 hr4 min 1 hr
t is in minutes, rates must
be converted to mph!
4 mi 60 min mi60 hr4 min 1 hr
You don’t really
need to find the
functions to graph
these! Endpoints should be
open dots!
There are sharp points
on the (time, distance)
graph, so the
derivative (velocity)
would not exist!
98.
5 mi 60 min mi50 hr6 min 1 hr
on [0, 6)
1 mi 60 min mi30 hr2 min 1 hr
on (8, 10]
FYI, to make conversions: 40 mi 1 hr 2 mi
min1 hr 60 min 3
on [2, 6)
Plot (6, 4), draw seg.
Change in miles is 0.
Change in miles is 2.
So from (8, 4), draw
segment to (10, 4+2).
Note: Constant rates of change, velocity, so
distance function are all linear pieces!
Ch 03 Homework Complete Solutions V2 Part 1: S. Stirling Name _________________________________
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On [2, 4) change in time is 4. 30 mi 1 hr 1 mi
1 hr 60 min 2 min
velocity
1 mi 4 min2 mi
2 min 1 change in distance.
Plot (0+4, 0+2) or (4, 2). Make segment.
On (4, 6) change in time is 2.
velocity is 0. No change in distance.
Plot (4+2, 2+0) or (6, 2).
On (6, 10] change in time is 4. 60 mi 1 hr mi
1 1 hr 60 min min
velocity
mi 4 min1 4 mi
min 1 change in distance.
Plot (6+4, 2+4) or (10, 6).
You don’t need to find the
functions to graph these!
Or think units: 15000 mi 1 gal $1.55
( )1 yr mi 1 gal
23.250 $
yr
C xx
x
C is the annual cost.
migal
$yr
The rate of change in the cost with
respect to the mpg (fuel efficiency).
The rate of change in the cost at 15 mpg is decreasing
at a faster rate than at 35 mpg. (See above.) Both
decreasing, but the absolute value is greater.
The driver who gets 15 mpg would
benefit more, because the rate of change
at x = 15 is larger in absolute value than
at x = 35.
Ch 03 Homework Complete Solutions V2 Part 1: S. Stirling Name _________________________________
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S. Stirling 2016 - 2017 Page 21 of 41
Let 3( ) 9y f x x x
So 2( ) 3 9f x x
Tangent line(s) through 1, 9 would satisfy the equation:
1 9y m x would need the slope = the derivative…
2
3 2
3 2
3 9 1 9
3 3 9 9 9
3 3 9
y x x
y x x x
y x x x
just simplifying
Now you’re stuck, but the tangent line and the function have to
share a point…so the y-values would be the same for some x:
Now 3 3 2
3 2
9 3 3 9
0 2 3
x x x x x
x x
Solve for x.
20 2 3x x So 0x or 32
x so you get two points.
(2 points on the curve where tangent lines could occur. So you will
have two lines.)
For x = 0: 3(0) (0) 9(0) 0f the point
2(0) 3(0) 9 9f the slope
Tangent line through 0,0 is 9 0 0
9
y x
y x
For x = 3/2: 3
3 3 3 27 27 8192 2 2 8 2 8
f
2
3 3 27 36 93 92 2 4 4 4
f
Tangent line through 3 81,2 8 :
9 3 81
4 2 8y x
xy
The given point is not on
the curve!
(2)f
Ch 03 Homework Complete Solutions V2 Part 1: S. Stirling Name _________________________________
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S. Stirling 2016 - 2017 Page 22 of 41
Intentionally left blank
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S. Stirling 2016 - 2017 Page 23 of 41
Note: The book does their original set up a tiny bit differently
than we do (but they are equivalent)! So check your final
answers, and if you don’t get it correct, look at the process.
*4. Not using the product rule: 51
2 2( ) 4g s s s just distribute!
312 2
4 5( )
2 2g s s s
Power rule
1
221
( ) 4 52
g s s s
Factor out fractions and negative exponents
2
12
4 5( )
2
sg s
s
Equivalent and easier!
Remember this from the summer assignments?
Apply & Practice 3.3 Set 1: P 147-150
#4, 6, 10, 12, 13, 16, 20, 22, 24, 26
#27-57 (mult. of 3)
#65, 66
Don’t expand! Product rule is quicker!
On All of these, use function notation to
label your work!!
10. (my way)
12
( )1 1
s sh s
s s
1 12 2
21
2
11 12
( )
1
s s s
h s
s
1 1 12 2 2
2 21 1
2 2
1 11 12 2
1 1
s s s
s s
12
2 21
2
1 222
2 11
ss
ss
Ch 03 Homework Complete Solutions V2 Part 1: S. Stirling Name _________________________________
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S. Stirling 2016 - 2017 Page 24 of 41
*30. Alternate: multiply then quotient rule
(easier!!) Get one rational 1st! 5 4
4 1( )
1 1
x x xf x x
x x
5 4 5 4
2
1 1( )
1
x x x x x xf x
x
4 3 5 4
2
5 4 1 1
1
x x x x x
x
5 4 3
2
4 2 4
1
x x x
x
3 2
2
2 2 2
1
x x x
x
22 1
1 1 1 1
x
x x x x
2
2, 1
1x
x
They’re gonna use Product rule…BIG mistake!
They skipped
lots of algebraic
steps here!
33. Probably easier not using Product Rule.
Just expand. Easiest is the Chain Rule, but you
haven’t learned that yet.
Distributing will get
you down to 2 terms,
so easier. Product
Rule would be a
disaster!
Just use the
Difference Rule now,
keeps the expressions
easy to simplify.
Ch 03 Homework Complete Solutions V2 Part 1: S. Stirling Name _________________________________
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S. Stirling 2016 - 2017 Page 25 of 41
Could do this with fractional exponents!
Note 1 2
2
1ds s
dx s
Used 2 21 cot csc . You may not need to simplify it this far.
*54. Alternate: Group factors 1st!
( ) 2sin cosf x x x
2
( ) 2cos cos 2sin cos
2cos 2sin cos
f x x x x x
x x x
Either of these expressions are good.
They used 2 2cos sin cos 2 .
To see of this is equivalent to 2cos2x , put both into
Y= and check that you are getting the same values in
the Table. Or graph, and it should be the same.
*57. Alternate: Fractional exponents & Product Rule
12
12
1( )
44
xxe
f x e xx
312 2
32
32
1 1 1( )
4 4 2
12 1
8
2 1
8
x x
x
x
f x e x e x
e x x
e x
x
Remember this from
the summer
assignments?
They skipped
a lot of steps!
At π, on the unit circle, 1,0
2 2
1 0 1 1( )h
At π/2, on the unit circle, 0,1
( / 4) 1 0 1f
Ch 03 Homework Complete Solutions V2 Part 1: S. Stirling Name _________________________________
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Apply & Practice 3.3 Set 2: #68, 71, 80, 82, 91, 94, 97, 100, 101, 103, 106, 107
#109 – 117, 119, 121, 122, 137, 138, 139
The main idea? Find the derivative and
set it equal to zero.
cos sin 0xe x x
since 0xe just look at cos sin 0x x
cos sinx x in quadrant II, at 3
4x
2 1
29 3
y x
Rate = derivative.
Tan negative in
QII and QIV
Always write your answer as a point! x- and y- value!! 3 3
4 43 3 2sin
4 4 2f e e
Ch 03 Homework Complete Solutions V2 Part 1: S. Stirling Name _________________________________
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S. Stirling 2016 - 2017 Page 27 of 41
Translation:
point (2, 0)
f decreasing on (–, 2)
f increasing on (2, )
Translation:
f always positive
f always
decreasing
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S. Stirling 2016 - 2017 Page 28 of 41
Ch 03 Homework Complete Solutions V2 Part 1: S. Stirling Name _________________________________
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S. Stirling 2016 - 2017 Page 29 of 41
(b) The particle speeds up (accelerates) when
a > 0 and slows down when a < 0.
Answers will vary.
s = position
v = velocity
a = acceleration
v +
a – slow dwn
v –
a – spd up
v –
a + slow
dwn
v +
a + spd
up
2
2
m3 36 3 27 sec
m3 2 3 6 sec
v
a
When velocity & acceleration have opposite signs,
the object is slowing down, speed decreasing
(opposite forces). Think gravity & positive velocity.
Ch 03 Homework Complete Solutions V2 Part 1: S. Stirling Name _________________________________
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S. Stirling 2016 - 2017 Page 30 of 41
Challenge (optional):
1) Set Up, use what you know:
x-intercept at (1, 0): 2(1) (1) (1) 0
0
f a b c
a b c
(2, 7) on graph: 2(2) (2) (2) 7
4 2 7
f a b c
a b c
Slope 10 at (2, 7): (2) 2 (2) 10
4 10
f a b
a b
2) Solve Simultaneously:
0
4 2 7
3 7
a b c
a b c
a b
Now
3 7
4 10
3
a b
a b
a
And
3(3) 7
2
b
b
And
3 2 0
1
c
c
3) The equation is
2( ) 3 2 1f x x x
The main idea? Find the derivative.
Slope through ,1
xx
x
and 1,5 must =
the derivative of f. (the slope of the tangent
line)
Slope through 2 points = tangent slope:
2
511
1 1
x
x
x x
cross mult.
2
2 2
2
2
1 5 1 1 1
5 10 5 1 1
4 9 5 1
4 10 4 0
x x x x
x x x x x
x x x
x x
2 1 2 0
1 , 22
x x
x
Find points and slopes, then lines:
1
21 12 1 1
2
f
2
11 42 1 1
2
f
1
4 12
y x
and
2
2 22 1
f
2
12 1
2 1f
1 2 2y x
Ch 03 Homework Complete Solutions V2 Part 1: S. Stirling Name _________________________________
Calculus: Early Transcendental Functions, 4e Larson
S. Stirling 2016 - 2017 Page 31 of 41
18. Alternative: 2( ) 2 1g x x x Chain Rule
1
2 21( ) 2 1 2 22
g x x x x
1
2 2
1( )
( 1)
xg x
x
= ± 1 b/c 2x x or x
Apply & Practice 3.4 Set 1: P 161-165
#9-36 (mult. of 3), 17 derive
#39, 42 just find derive. by nderiv
#101, 150
Writing & Conceptual #139-145; #172-173
Whole class (if time): #152, 165
Rewriting with negative exponent
& using Chain Rule is easier &
quicker than the Quotient Rule.
Can use: 2u u
Then knowledge of
the graph.
Again Chain Rule is easier
than the Quotient Rule.
27. 42( ) 2f x x x
Main property, Product rule:
f a b
f a b a b
4 32( ) 2 2 4 2 1f x x x x x
4 32
3
3
( ) 2 2 4 2
2 2 2 2
2 2 3 2
f x x x x x
x x x x
x x x
For b , you should
apply the Chain Rule
4
3
2
4 2 1
b x
b x
30. 2 2116
2y x x
1
2 2 2116
2y x x
Main property, Product rule:
f a b
f a b a b
1 12 2 22 2
1 12 3 22 2
12 2 22
2 2 2
1 12 22 2
1 116 16 2
2 2
116 16
2
116 2 16
2
32 2 32 3
2 16 2 16
y x x x x x
x x x x
x x x x
x x x x x
x x
For b , you should apply
the Chain Rule
12 2
12 2
16
116 2
2
b x
b x x
#27 & 30, give your answers in simplified factored form.
Ch 03 Homework Complete Solutions V2 Part 1: S. Stirling Name _________________________________
Calculus: Early Transcendental Functions, 4e Larson
S. Stirling 2016 - 2017 Page 32 of 41
33.
2
2
5( )
2
xg x
x
Main property, Chain Rule:
2g x u
2g x u u
2
22 2
2
32
5 1 10 22
2 2
2 5 2 10
2
x x xg x
x x
x x x
x
For u , you should apply the
Quotient rule
au
b
2
a b a bu
b
2
5
2
xu
x
2
22
2 2
22
2
22
1 2 5 2
2
2 2 10
2
1 10 2
2
x x xu
x
x x x
x
x x
x
Similar to #33, but this time I did most of the work within the
problem and some in my head. Do what you need to do!
Straight forward Chain Rule.
Ch 03 Homework Complete Solutions V2 Part 1: S. Stirling Name _________________________________
Calculus: Early Transcendental Functions, 4e Larson
S. Stirling 2016 - 2017 Page 33 of 41
x
y
FYI only
FYI only
101. Alternative:
22
22
( ) 6 1 2
12 1
f x x x
x x
22 2
22 2 2
2 2 2
2 2
( ) 12 1 12 2 1 2
12 1 48 1
12 1 1 4
12 1 5 1
f x x x x x
x x x
x x x
x x
Gets it into factored form easier than the other
method. This will be helpful when trying to find
horizontal tangents.
Using the Product
Rule w/ Chain
Rule of course.
Using the
distributive
property.
(a&b) Use Y1 = (X^2 – 9)√(X+2)
Y2 = nDeriv(Y1, X, X)
Y2(2) 6.75 6.75 2 10y t
FYI only
Ch 03 Homework Complete Solutions V2 Part 1: S. Stirling Name _________________________________
Calculus: Early Transcendental Functions, 4e Larson
S. Stirling 2016 - 2017 Page 34 of 41
The language here is very important! “The derivative is negative, so f is decreasing”…
AP Loves these!
Note: at the endpoint of f, there
would be a vertical tangent line.
So on f , there is a vertical
asymptote there.
Note: Horizontal compression
would make the graph steeper and
the tangent lines steeper. 3 times
steeper.
Ch 03 Homework Complete Solutions V2 Part 1: S. Stirling Name _________________________________
Calculus: Early Transcendental Functions, 4e Larson
S. Stirling 2016 - 2017 Page 35 of 41
AP Loves these too!
Ch 03 Homework Complete Solutions V2 Part 1: S. Stirling Name _________________________________
Calculus: Early Transcendental Functions, 4e Larson
S. Stirling 2016 - 2017 Page 36 of 41
OR Use Y1 = (cos(πX)+1)/X
nDeriv(Y1, X, X) graph
Use transformations to confirm your results.
Apply & Practice 3.4 Set 2: P 161-165
#45 Use the calculator.
#48, 50, 51 Sketch graphs too.
#57-99 (mult. of 3) Skip #93!
#103-105 Second derivatives.
#114, 118, 119 Tangent lines & evaluate
Ch 03 Homework Complete Solutions V2 Part 1: S. Stirling Name _________________________________
Calculus: Early Transcendental Functions, 4e Larson
S. Stirling 2016 - 2017 Page 37 of 41
#104 is on the next page
USE LOG PROPERTIES
to your advantage!!!
They factored and used the Product Rule only
once. If you didn’t, you would have to use the
Product Rule on each of two terms. That’s the
hard way.
Note: 3e is a
number, a scalar
multiple. No
Product Rule here.
Ch 03 Homework Complete Solutions V2 Part 1: S. Stirling Name _________________________________
Calculus: Early Transcendental Functions, 4e Larson
S. Stirling 2016 - 2017 Page 38 of 41
12 24
y x
3 2 2
2 4 2y x
2
( ) sec( )f x x
Ch 03 Homework Complete Solutions V2 Part 1: S. Stirling Name _________________________________
Calculus: Early Transcendental Functions, 4e Larson
S. Stirling 2016 - 2017 Page 39 of 41
You will need the identity: 2cos(2 ) 1 2sinx x
Apply & Practice 3.4 Set 3: #153, 158 Tangent lines & evaluate
#160 Application
#183-185 T or F
#123-129, 131-133, 135 Deriv. other bases.
#174 prove deriv. of |x|
#175 – 177 apply deriv. of |x|
#179, 181 a & d Do the linear approx. ONLY
Ch 03 Homework Complete Solutions V2 Part 1: S. Stirling Name _________________________________
Calculus: Early Transcendental Functions, 4e Larson
S. Stirling 2016 - 2017 Page 40 of 41
USE LOG PROPERTIES to your advantage!!!
Ch 03 Homework Complete Solutions V2 Part 1: S. Stirling Name _________________________________
Calculus: Early Transcendental Functions, 4e Larson
S. Stirling 2016 - 2017 Page 41 of 41
Exercises 179-181 Find linear approximation at the given a value.