Question

Jika fungsi f(x) = 1/4 sin 4x maka nilai nilai dari f'(1/4π) adalah...
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Answer 1

Verified answer

f(x) = sin(4x)/4

Misal, a = 4x

maka, da/dx = 4

misal, b = sin(a)

maka, db/da = cos(a)

misal, y = b/4

maka, dy/db = 1/4

Maka, f'(x) = dy/dx = dy/db . db/da . da/dx

= (1/4).(cos(a))4

= cos(a)

= cos(4x)

f'(π/4) = cos(4.π/4) = cos(π) = -1