This might be a rule, but i'm not sure
Show all work...
the choices are..
A. -1
B. 0
C. -2sin(2x)
D. -2(cosx + sinx)
E. 2(cosx - sin x)
2007-12-31 13:12:16 · 5 answers · asked by Anish C 1 in Science & Mathematics ➔ Mathematics
y = cos^2 x - sin^2 x = cos2x
=> y' = -2sin2x
2007-12-31 13:32:25 · answer #1 · answered by namvt2000 6 · 1⤊ 0⤋
Before differentiating, simplify first
y = cos^2 x - sin^2 x = cos(2x)
y ' = -2 sin(2x)
Answer is C.
2008-01-01 00:05:28 · answer #2 · answered by Darkskinnyboy 6 · 0⤊ 0⤋
There are many ways to solve this. The easiest way is to note that y = cos^2 x - sin^2 x = cos(2x), and applying the chain rule you get dy/dx = -2sin(2x).
2007-12-31 21:45:27 · answer #3 · answered by 太极拳 ‽-ℓ-‽ 5 · 1⤊ 0⤋
If y = cos^2 x - sin^2 x, then y' = ?
Before you differentiate, simplify
y = cos^2 x - sin^2 x = cos(2x)
y ' = -2 sin(2x)
Answer is C
2007-12-31 21:18:48 · answer #4 · answered by Any day 6 · 2⤊ 0⤋
y = (cos x) ² - (sin x) ²
dy/dx = 2(cos x)(- sin x) - 2 (sin x)(cos x)
dy/dx = - 4 sin x cos x
dy/dx = (-2) (2 sin x cos x)
dy/dx = - 2 sin 2x
OPTION C
2008-01-01 05:43:31 · answer #5 · answered by Como 7 · 1⤊ 0⤋