Q. h(x)=arctan(−2x)h′(−7)=□Use an exact expression.
Find derivative using chain rule: step_1: Find the derivative of h(x)=arctan(−2x). To find the derivative of h(x), we will use the chain rule. 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.
Apply chain rule to h(x): step_2: Apply the chain rule to h(x)=arctan(−2x). The outer function is arctan(u), and the inner function is u=−2x. The derivative of arctan(u) with respect to u is 1+u21. The derivative of u=−2x with respect to x is −21.
Combine derivatives to find h′(x): step_3: Combine the derivatives to find h′(x). h′(x)=1+u21⋅dxdu =1+(−2x)21⋅(−21) =1+4x21⋅(−21) =−2⋅(1+4x2)1 =−2+2x21
Simplify expression for h′(x): step_4: Simplify the expression for h′(x).h′(x)=−2+(2x2)1=−2(1+4x2)1=−2+4x21
Evaluate h′(x) at x=−7: step_5: Evaluate h′(x) at x=−7.h′(−7)=−1/(2+(−7)2/4)=−1/(2+49/4)=−1/(2+12.25)=−1/(14.25)=−1/14.25
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