-sin^2x
i dont get why it turn out to be -2sinx cosx
2007-07-17 19:23:51 · 4 answers · asked by biomes 1 in Science & Mathematics ➔ Mathematics
y = - sin ² x
y = - (sin x) ²
dy / dx = - 2(sin x)^1 (cos x)
dy/dx = - 2 (sin x) (cos x)
dy /dx = - sin 2x
2007-07-17 20:15:59 · answer #1 · answered by Como 7 · 0⤊ 0⤋
-sin^2x can be written as -(sin x)^2
we know that the derivative of sin x is cos x
and the derivative of v^2 is 2v
using the chain rule
d ( - sin^2 x)/dx = 2 (-sin x) (cosx) = - 2sin x cos x
2007-07-18 02:30:30 · answer #2 · answered by TENBONG 3 · 0⤊ 0⤋
sin 2x = 2 sin x cos x , trigonometric identity.
2007-07-18 02:30:40 · answer #3 · answered by thepaladin38 5 · 0⤊ 0⤋
Use the Chain rule...
- d/dx (sinX)^2 move the neg. outside...
So... - 2(sinX)(CosX) derivative of SinX is Cos X
Ya dig?
2007-07-18 02:32:34 · answer #4 · answered by Anonymous · 0⤊ 0⤋