1. ## Differentiation

I am having a problem with these two questions

1) f(t) =(3t-2) sin2t

2) f(theta) = 2cos(3theta-1)/3 theta

Help would be appreciated

2. Originally Posted by Jaffa
I am having a problem with these two questions

1) f(t) =(3t-2) sin2t

2) f(theta) = 2cos(3theta-1)/3 theta

Help would be appreciated
OK but ... what is the question you are supposed to answer ?

3. Sorry, did not make myself clear,I have to differentiate the functions

4. The first question is an application of the product rule, the second is an application of the quotient rule. Check them out in your book.

5. Originally Posted by Jaffa
I am having a problem with these two questions

1) f(t) =(3t-2) sin2t

2) f(theta) = 2cos(3theta-1)/3 theta

Help would be appreciated
$f(t) = (3t - 2) * sin (2t)$
Using the product and chain rules:

$f'(t) = (3t - 2) * 2 cos (2t) + sin (2t) * 3$
$f'(t) = 2*(3t - 2) cos (2t) + 3 sin (2t)$

$f(\theta) = \frac{2 cos (3\theta -1)}{3\theta}$
Using the chain rule and quotient rule:
$f'(\theta) = \frac{3\theta * -6 sin (3\theta-1) - 6 cos (3\theta-1)}{(3\theta)^2}$
$f'(\theta) = \frac{-18\theta * sin (3\theta-1) - 6 cos (3\theta-1)}{9\theta^2}$
$f'(\theta) = \frac{-6\theta * sin (3\theta-1) - 2 cos (3\theta-1)}{3\theta^2}$