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En
 one year ago
PLEASE HELP!!!!!!!!!
find the derivative of z=1/2x+1/4 sin2x.
i only got 1/2+1/2 cos2x but my book says the answer is cos^2x... pleaaseee explain it to me.
En
 one year ago
PLEASE HELP!!!!!!!!! find the derivative of z=1/2x+1/4 sin2x. i only got 1/2+1/2 cos2x but my book says the answer is cos^2x... pleaaseee explain it to me.

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Loser66
 one year ago
Best ResponseYou've already chosen the best response.1I think IrishBoy explained you already, right? they are the same.

En
 one year ago
Best ResponseYou've already chosen the best response.0i still dont get it.. i tried using the double angle but i only get 2cos^2x :/

Loser66
 one year ago
Best ResponseYou've already chosen the best response.1\(cos (2x) =2cos^2(x) 1\\2cos^2(x) = cos (2x) +1\\cos^2(x) = \dfrac{cos(2x) +1}{2}= \dfrac{1}{2}+\dfrac{cos(2x)}{2}\)

En
 one year ago
Best ResponseYou've already chosen the best response.0so the only equivalent of cos(2x) is can use is 2cos^2x1? i cant use the \[\cos2x=\cos^2x\sin^2x\] ?

Loser66
 one year ago
Best ResponseYou've already chosen the best response.1Yes, just take one more step : sin^2 = 1  cos^2 to get cos (2x) = cos^2  1+ cos^2 = 2cos^2 1

Loser66
 one year ago
Best ResponseYou've already chosen the best response.1it is back to my comment.

En
 one year ago
Best ResponseYou've already chosen the best response.0\[=1/2(1+\cos^2x\sin^2x) =1/2(\cos^2x+\cos^2x)=1/2(2\cos^2x)=\cos^2x\] is this fine?

En
 one year ago
Best ResponseYou've already chosen the best response.0thanks :) sorry for the trouble.
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