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January 29, 2015

January 29, 2015

Posted by **Sara** on Saturday, June 19, 2010 at 1:06pm.

2sinxcosx + cosx =0

2sinxcosx = -cosx

2sinx = -cosx/cosx

sinx = -1/2

{210, 330)

Is this correct?

- trig -
**Reiny**, Saturday, June 19, 2010 at 5:41pmno , you only have half the answers

2sinxcosx + cosx =0

cosx(2sinx + 1) = 0

cosx = 0 or sinx = -1/2

if cosx = 0, x = 90° , 270°

if sinx = -1/2, x = 210°, 330°

(you only had the last case)

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