It's a math problem T_T I can't solve it
2007-09-09 04:59:04 · 3 answers · asked by thu p 1 in Science & Mathematics ➔ Mathematics
1-2cos(x) = 0
cos(x) = 1/2
x = 60, 300 degrees
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Ideas: Solve for cos(x) directly.
2007-09-09 05:04:12 · answer #1 · answered by sahsjing 7 · 0⤊ 0⤋
(i) cos x = cos^2 (x/2) - sin^2 (x/2)
(ii) 1 = cos^2 (x/2) - sin^2 (x/2)
subtract twice i from (ii)
1 - 2cos x = -cos^2 (x/2) + sin^2 (x/2)
1-2cos x = (sin (x/2) - cos(x/2))(sin(x/2) + cos(x/2))
2007-09-09 05:17:28 · answer #2 · answered by orefilwe p 1 · 0⤊ 0⤋
(i) cos x = cos^2 (x/2) - sin^2 (x/2)
(ii) 1 = cos^2 (x/2) - sin^2 (x/2)
subtract twice i from (ii)
1 - 2cos x = -cos^2 (x/2) + sin^2 (x/2)
1-2cos x = (sin (x/2) - cos(x/2))(sin(x/2) + cos(x/2))
2007-09-09 05:13:32 · answer #3 · answered by Amit Y 5 · 0⤊ 0⤋