Find the 99th derivative of sin(-x).
For the function f(x) = sin (-x), as the sine function is odd, f(x) = -sin x. If F(n) represents the nth derivative,
F(0) = -sin x
F(1) = -cos x
F(2) = sin x
F(3) = cos x
F(4) = -sin x
F(5) = -cos x
It is seen that the derivative repeats after the function has been differentiated 4 times.
f(99) = f(3 + 4*24) = f(3) = cos x
The 99th derivative of f(x) = sin(-x) is cos x
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