Lesson 6.5 and 6.6 - Intro to Natural Logarithm and Derivative€¦ · Lesson 6.5 and 6.6 Intro to...
Transcript of Lesson 6.5 and 6.6 - Intro to Natural Logarithm and Derivative€¦ · Lesson 6.5 and 6.6 Intro to...
Lesson 6.5 and 6.6 Intro to Natural Logarithm and Derivative
Let's now take a look at y = ex
= 2.718 281 828 459
Let's now take a look at y = lnx
This function is known as the natural logarithm of x and is defined as ln x = logex.
Let's now compare y = ex and y = ln x
y = ex y = ln x
Domain:
Range:
Increasing/Decreasing
yintercept
xintercept
asymptote
max/min points
inflection
concavity
Evaluate the following:
(a) e3
(b) e1/2
(c) ln 10
(d) ln (5)
(e) ln e
Lesson 6.5 and 6.6 Intro to Natural Logarithm and Derivative
Properties of exponential and logarithmic functions
ln ex = x and elnx = x
Example Bacterial GrowthThe population of a bacterial culture as a function of time is given by the equation P(t) = 200e0.094t , where P is the population after t days.
(a) What is the initial population of the bacterial culture?
(b) Estimate the population after 3 days.
(c) How long will the bacterial culture take to double its population?
Derivative of the exponential function
Given the exponential function y = bx
dy/dx = (lnb)bx
Example #1Determine the derivative of each function.
(a) y = 3x
(b) y = ex
Example #2Find the equation of the line tangent to the curve y = 2e x at x = ln3
Example #3A biologist is studying the increase in the population of a particular insect in a provincial park. The population triples every week. Assume the population continues to increase at this rate and initially there are 100 insects.(a) Determine the number of insects present after 4 weeks(b) How fast is the number of insects increasing
(i) when they are initially discovered?(ii) at the end of 4 weeks?