prove trignometry identities

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1. csc(2x)=1/2sec(x)*csc(x) :(

2. cos 2x+cosx=0 Find x in radians
 

skeeter

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Dec 15, 2005
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1. csc(2x) = 1/sin(2x) = 1/(2sinx*cosx) = (1/2)(1/sinx)(1/cosx) = ?

2. cos(2x) + cosx = 0
2cos<sup>2</sup>x - 1 + cosx = 0
2cos<sup>2</sup>x + cosx - 1 = 0
(2cosx - 1)(cosx + 1) = 0

hard part is done ... you finish it up.
 
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