Q. Find the derivative of the following function.y=log5(−4x5)Answer: y′=
Identify Function & Derivative Type: Identify the function and the type of derivative to be found.We need to find the derivative of the function y=log5(−4x5) with respect to x. This involves using the chain rule and the logarithmic differentiation rule.
Apply Chain Rule: Apply the chain rule for derivatives.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. For the logarithmic function y=log5(u), where u=−4x5, the derivative with respect to x is (1/u)⋅(du/dx).
Differentiate Inner Function: Differentiate the inner function u=−4x5 with respect to x. The derivative of u with respect to x is dxdu=−4×5x5−1=−20x4.
Apply Change of Base Formula: Apply the change of base formula for logarithms. The change of base formula is logb(a)=logc(b)logc(a). We can rewrite y as log5(−4x5)=log(5)log(−4x5), where the base c of the logarithm is the natural logarithm (base e).
Combine Results for Derivative: Combine the results from Steps 2, 3, and 4 to find the derivative.Using the chain rule, the derivative of y with respect to x is y′=(−4x5)1×log(5)−20x4.
Simplify Derivative Expression: Simplify the expression for the derivative.y′=−4x5−20x4/log(5)=4x20/log(5)=x⋅log(5)5.
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