Skip to main content
Ch. 3 - Derivatives
Hass - Thomas' Calculus 15th Edition
Hass15th EditionThomas' CalculusISBN: 9780137616077당신이 사용하는 게 아니라요?교과서 변경
3장, 문제 3.6.60

Second Derivatives


Find y'' in Exercises 59–64.


y = (1 − √x)⁻¹

검증된 단계별 안내
1
First, rewrite the given function \( y = (1 - \sqrt{x})^{-1} \) in a more convenient form for differentiation. This can be expressed as \( y = \frac{1}{1 - \sqrt{x}} \).
To find the first derivative \( y' \), apply the chain rule and the power rule. Start by differentiating the outer function \( u^{-1} \) where \( u = 1 - \sqrt{x} \). The derivative of \( u^{-1} \) is \( -u^{-2} \).
Next, differentiate the inner function \( u = 1 - \sqrt{x} \). The derivative of \( \sqrt{x} \) is \( \frac{1}{2\sqrt{x}} \), so the derivative of \( u \) is \( -\frac{1}{2\sqrt{x}} \).
Combine these results using the chain rule: \( y' = -\frac{1}{(1 - \sqrt{x})^2} \cdot (-\frac{1}{2\sqrt{x}}) \). Simplify this expression to find \( y' \).
To find the second derivative \( y'' \), differentiate \( y' \) with respect to \( x \) again. Use the quotient rule or product rule as needed, and simplify the resulting expression to obtain \( y'' \).

비슷한 문제에 대한 검증된 영상 답변:

이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
영상 길이:
6m
도움이 되었나요?

주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

Chain Rule

The chain rule is a fundamental technique in calculus used to differentiate composite functions. It states that if a function y = f(g(x)) is composed of two functions, the derivative y' is found by multiplying the derivative of the outer function f with respect to the inner function g by the derivative of the inner function g with respect to x. This rule is essential when dealing with nested functions, such as y = (1 − √x)⁻¹.
추천 영상:
05:02
Intro to the Chain Rule

Power Rule

The power rule is a basic rule for differentiation that applies to functions of the form y = x^n, where n is any real number. The derivative of y with respect to x is given by y' = n*x^(n-1). This rule is crucial for differentiating terms like (1 − √x)⁻¹, where the exponent is negative, and it helps simplify the process of finding the first and second derivatives.
추천 영상:

Second Derivative

The second derivative, denoted as y'' or d²y/dx², represents the derivative of the first derivative y'. It provides information about the concavity and inflection points of the original function y. Calculating the second derivative involves differentiating the first derivative, often requiring the application of rules like the chain rule and power rule multiple times, especially in complex functions like y = (1 − √x)⁻¹.
추천 영상:
06:02
The Second Derivative Test: Finding Local Extrema