Q. Let g(x)=81x3+21x−41 and let h be the inverse function of g. Notice that g(2)=47.h′(47)=
Find g′(x): First, we need to find the derivative of g(x), which is g′(x). So let's differentiate g(x)=81x3+21x−41.
Calculate g′(2):g′(x)=83x2+21.
Use formula for inverse function derivative: Now, we know that g(2)=47, so we need to find g′(2) to use in the formula for the derivative of the inverse function.
Find g−1(47):g′(2)=(83)(2)2+21=(83)(4)+21=3+21=3.5 or 27.
Plug in g′(2) into formula: The formula for the derivative of the inverse function at a point y is g′(g−1(y))1. We have y=47 and we need to find g−1(47), but we already know that g(2)=47, so g−1(47)=2.
Simplify expression: Now we plug in g′(2) into the formula: h′(47)=g′(2)1=(27)1.
Simplify expression: Now we plug in g′(2) into the formula: h′(47)=g′(2)1=(27)1.Simplify the expression: h′(47)=(27)1=72.
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