a. sin 10x
b. sin 6x
c. cos 10x
d. cos 6x
e. none of these here
2007-03-19 20:56:55 · 5 answers · asked by Momof5 1 in Science & Mathematics ➔ Mathematics
This is a Trig Identity
Sin (x+y) = sin(x)cos(y) + sin(y)cos(x)
x = 8x
y = 2x
Sin (8x + 2x) = sin(10x)
2007-03-19 21:03:10 · answer #1 · answered by Tony R 2 · 0⤊ 0⤋
a. sin 10x
by the standard formula: sin(A+B)=sin A cos B + cos A sin B,
we get: sin (8x+2x) = sin 8x cos 2x + cos 8x sin 2x
sin 10x
2007-03-20 04:08:32 · answer #2 · answered by krizy 2 · 0⤊ 0⤋
sin (A+B) = sin A cos B + cos A sin B
here A=8x
B=2x
sin 8x cos 2x + cos 8x sin 2x =
sin (8x +2x) = sin (10x ) =
sin 10x
2007-03-20 04:17:51 · answer #3 · answered by vishwa s 2 · 0⤊ 0⤋
sin 8x cos 2x + cos 8x sin 2x
= sin (8x + 2x)
= sin 10x
so the answer is A.
identity: sin(A+B) = sinA cosB + cosA sinB
proof of this identity can be found here:
http://www.themathpage.com/aTrig/sum-proof.htm
2007-03-20 04:24:04 · answer #4 · answered by zzzonked 2 · 0⤊ 0⤋
sin (8x + 2x) = sin8x.cos2x + cos8x.sin2x
sin(8x + 2x) = sin10x
Answer a
2007-03-20 04:02:16 · answer #5 · answered by Como 7 · 0⤊ 0⤋