Jawabanmu

2014-05-30T10:33:06+07:00
Rumus f'(a/b)=(a'b-ab')/b^2. cotan = cos/sin. Masukin ke rumus tadi.

Misalkan 3x = p; f(x)=cotanp

df/dp.f(x).dx/dp (aturan rantai)

turunan f(x) = -sinp.sinp - (cosp.cosp)/sin^2p
= -(sin^2 p + cos^2p)/sin^2p = -1/sin^2p
= -cosec^2p

dx/dp = 3

jadi f'(x) = -cosec^2p x 3 (balikin lagi p jadi x)

f'(x) = -3 cosec^2 3x

tinggal masukin x = pi/4

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