Q. y=arctan(−4x)Evaluate dxdy at x=3.Use an exact expression.
Differentiate using chain rule: step_1: Differentiate y=arctan(−4x) with respect to x using the chain rule.The derivative of arctan(u) with respect to u is 1+u21, so by the chain rule, dxdy=(1+(−4x)21)∗dxd(−4x).
Calculate derivative of −4x: step_2: Calculate the derivative of −4x with respect to x.dxd(−4x)=−4.
Substitute derivative into result: step_3: Substitute the derivative of −4x into the result from step 1.\frac{dy}{dx} = \left(\frac{1}{1+(\-4x)^2}\right) * (\-4).
Simplify expression for dxdy: step_4: Simplify the expression for dxdy.dxdy=1+16x2−4.
Evaluate dxdy at x=3: step_5: Evaluate dxdy at x=3.dxdy at x=3 is −1+16(3)24.
Calculate exact expression at x=3: step_6: Calculate the exact expression for dxdy at x=3.dxdy at x=3 is −1+16⋅94.
Simplify the denominator: step_7: Simplify the denominator.1+16×9=1+144.
Add numbers in the denominator: step_8: Add the numbers in the denominator. 1+144=145.
Write final expression for dxdy: step_9: Write the final expression for dxdy at x=3.dxdy at x=3 is −1454.
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