homework
2007-06-30 03:58:18 · 7 answers · asked by Lee YW 1 in Science & Mathematics ➔ Mathematics
use the identity sin2A = 2sinAcosA
3(2sinAcosA) = 2 sinA
6sinAcosA - 2sinA = 0
2sinA(3cosA - 1) = 0
This result holds when sinA = 0 (A=0, 180)
and also when cosA = ⅓ (A=70.529, 289.471)
2007-06-30 04:02:27 · answer #1 · answered by Astral Walker 7 · 0⤊ 0⤋
3sin 2A = 2sin A
3sin A cosA = 2sin A
3sin A cosA - 2sin A = 0
sin A (3cos A - 2) = 0
sin A = 0 at A = 0, pi, 2 pi.
(3cos A - 2) = 0, or cos A = 2/3; A = .84 radians, and 2 pi - .84 radians
2007-06-30 11:09:20 · answer #2 · answered by fcas80 7 · 0⤊ 0⤋
6.sin A.cos A - 2.sin A = 0
2 sin A.(3 cos A - 1) = 0
sin A = 0 , cos A = 1 / 3
A = 0° ,180° , 360° , 70.5° , 290°
2007-06-30 11:43:37 · answer #3 · answered by Como 7 · 0⤊ 0⤋
3 sin 2A = 2 sin A
3 ( 2 sin A cos A ) = 2 sin A
3 cos A = 1
cos A = 1/ 3
A = 70.53 deg . . . . A = 289.47 deg
2007-06-30 11:12:51 · answer #4 · answered by CPUcate 6 · 0⤊ 0⤋
3sin2A=2sinA
3(2sinAcosA) = 2 sinA
6 cosA = 2
cosA = 1/3
A = cos^-1(1/3)
Also when A = 0; sin(0) is 0, so the equation is also true.
2007-06-30 11:02:29 · answer #5 · answered by Anonymous · 0⤊ 0⤋
Answer: A = 0, 1.2310, Pi, 2*Pi.
Checks out by substitution.
2007-06-30 11:15:12 · answer #6 · answered by ? 5 · 0⤊ 0⤋
6sinAcosA=2sinA;
sinA=0,A=0,180,360answer
OR
cosA=1/3=0.333=cos70.53
A=70.53,289.47answer
2007-06-30 11:04:12 · answer #7 · answered by Anonymous · 0⤊ 0⤋