`f(theta) = (theta + 1)cos(theta)` Find the derivative of the trigonometric function.

Expert Answers
hkj1385 eNotes educator| Certified Educator

Note:- if y = cos(x) ; then dy/dx = -sinx

Now, 

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`f(theta) = {(theta)+1}cos(theta)`

thus, `f'(theta) = cos(theta) - {(theta) + 1}sin(theta)`

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