Thread: Trig Differentation

I need help to differentate these 2 questions. Thanks for your help in advance.

y = sinx/1+cosx
For this one, i tried the quotient rule and ended off with cosx + cos^2(x) + sin^2(x)/ 1+cosx^2 which is not the right answer.

y = cos(sin2x)
I tried product rule and for the wrong answer.

The first one is correct IF you square the entire denominator.
Then use cos^2(x) + sin^2(x)=1 AND reduce.
You need the chain rule on the second one.

Originally Posted by proski117

I need help to differentate these 2 questions. Thanks for your help in advance.

y = sinx/1+cosx
For this one, i tried the quotient rule and ended off with cosx + cos^2(x) + sin^2(x)/ 1+cosx^2 which is not the right answer.

y = cos(sin2x)
I tried product rule and for the wrong answer.

I used the quotient rule on number 1 and got

can you guys show me how to do the second one? i dont know what im doing wrong when using the chain rule

Originally Posted by proski117

can you guys show me how to do the second one? i dont know what im doing wrong when using the chain rule

y = cos(sin2x)



note that 2cos(2x) is the derivative of sin(2x)