2007-03-30 11:36:21 · 5 answers · asked by PDF 2 in Science & Mathematics ➔ Mathematics
2cosx - 1 = 0
2 cosx = 1
cosx = 1/2
Well, you should know that cos = 1/2 at 60 degrees. Since it's positive, it could be in the first or fourth quadrant. There are different answers if your teacher requests radians instead of degrees. Here's all of the answers...
60 degrees
300 degrees (that's the -60 degrees, in Quadrant IV)
pi/3
5pi/3 (that's pi/3 in Quadrant IV)
If you have a question about how I knew that cosx = 1/2 at 60 degrees, feel free to IM me, and I can explain the hand trick, if you havnen't learned it already.
2007-03-30 12:27:51 · answer #1 · answered by its_victoria08 6 · 2⤊ 0⤋
2cosx 1 0
2016-09-29 22:07:21 · answer #2 · answered by ? 4 · 0⤊ 0⤋
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RE:
hello I need to know how to find X when 2cosx-1=0 and why?
2015-08-18 05:47:20 · answer #3 · answered by ? 1 · 0⤊ 0⤋
2cosx -1 =0
2cosx =1
cosx =1/2
Now, you tell me what angle has a cosine of 1/2? Hint: 0, 30, 45, 60 or 90?
2007-03-30 11:42:43 · answer #4 · answered by smarties 6 · 1⤊ 0⤋
28
2016-03-20 06:52:08 · answer #5 · answered by ? 4 · 0⤊ 0⤋
Add 1 to each side of the equation:
2cos x = 1
Divide by 2:
cos x = 1/2
x = 2n*pi +- pi/3 where n is any integer.
2007-03-30 11:43:36 · answer #6 · answered by Anonymous · 0⤊ 0⤋
cos x=1/2 and you should know that x= pi/3
and x=5pi/3
2007-03-30 11:45:34 · answer #7 · answered by santmann2002 7 · 0⤊ 0⤋