Q. Given the function f(x)=(−9x−5)31, find f′(x) in any form.
Identify function: Identify the function to differentiate.We are given the function f(x)=(−9x−5)31, which is a composition of functions. We need to find its derivative f′(x).
Apply chain rule: Apply the chain rule for differentiation.The chain rule states that the derivative of a composite function is the derivative of the outer function evaluated at the inner function times the derivative of the inner function. In this case, the outer function is u(1/3) and the inner function is u=−9x−5.
Differentiate outer function: Differentiate the outer function with respect to the inner function.Let u=−9x−5. Then the outer function is u(1/3). The derivative of u(1/3) with respect to u is (1/3)u(−2/3).
Differentiate inner function: Differentiate the inner function with respect to x. The derivative of u=−9x−5 with respect to x is dxdu=−9.
Apply chain rule multiplication: Apply the chain rule by multiplying the derivatives from Step 3 and Step 4.f'(x) = \left(\frac{d}{dx} of the outer function evaluated at the inner function\) × \left(\frac{d}{dx} of the inner function\)f′(x)=(31)(−9x−5)−32×(−9)
Simplify derivative: Simplify the expression for the derivative. f′(x)=−3(−9x−5)−32
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