`f(t) = cos(t)/t` Find the derivative of the trigonometric function.

Expert Answers
hkj1385 eNotes educator| Certified Educator

Note:- 1) If y = cosx ; then dy/dx = -sinx

2) If y = u/v ; where 'u' & 'v' are functions of x or constants ; then dy/dx = [vu'-uv']/(v^2)

Now, 

`f(t) = cost/t`

`f'(t) = [-t*sint - cost]/t^2`

`or, f'(t) = -[t*sint-cost]/t^2`

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