Watching an elevator An observer is 20 m above the ground floor of a large hotel atrium looking at a glass-enclosed elevator shaft that is 20 m horizontally from the observer (see figure). The angle of elevation of the elevator is the angle that the observer’s line of sight makes with the horizontal (it may be positive or negative). Assuming the elevator rises at a rate of 5 m/s, what is the rate of change of the angle of elevation when the elevator is 10 m above the ground? When the elevator is 40 m above the ground? <IMAGE>
Ch. 3 - Derivatives
Briggs3rd EditionCalculus: Early TranscendentalsISBN: 9780136847243Not the one you use?Change textbook
Chapter 3, Problem 3.5.62
Find y'' for the following functions.
y = tan x
Verified step by step guidance1
Start by identifying the function y = tan(x). To find the second derivative y'', we first need to find the first derivative y'.
Recall the derivative of tan(x) with respect to x is sec^2(x). Therefore, y' = sec^2(x).
Next, we need to find the derivative of y' to obtain y''. This means we need to differentiate sec^2(x) with respect to x.
Use the chain rule to differentiate sec^2(x). Let u = sec(x), then y' = u^2. The derivative of u^2 with respect to x is 2u * du/dx.
Now, find du/dx where u = sec(x). The derivative of sec(x) is sec(x)tan(x). Substitute back to get y'' = 2sec(x) * sec(x)tan(x) = 2sec^3(x)tan(x).

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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Second Derivative
The second derivative of a function measures the rate of change of the first derivative. It provides information about the concavity of the function and can indicate points of inflection where the function changes from concave up to concave down or vice versa. In this context, finding y'' involves differentiating the function y = tan x twice.
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Differentiation Rules
Differentiation rules are formulas and techniques used to compute the derivative of functions. Key rules include the power rule, product rule, quotient rule, and chain rule. For the function y = tan x, the derivative can be found using the quotient rule, as tan x can be expressed as sin x / cos x.
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Trigonometric Derivatives
Trigonometric derivatives are specific derivatives of trigonometric functions, which have unique rates of change. For example, the derivative of tan x is sec² x. Understanding these derivatives is essential for solving problems involving trigonometric functions, such as finding the second derivative of y = tan x.
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