Posted by Anonymous on Wednesday, February 22, 2012 at 11:11pm.
sin2x+cosx=0 , [180,180)
= 2sinxcosx+cosx=0
= cosx(2sinx+1)=0
cosx=0
x1=cos^1(0)
x1=90
x2=36090
x2=270
270 doesn't fit in [180,180) what do I do? Or maybe I did something wrong.
sinx=1/2
x1=sin^1(1/2)
x1=30
x2=18030
x2=150
is this correct?
Please and Thank you

Trig (Last URGENT)  Reiny, Wednesday, February 22, 2012 at 11:18pm
but your domain is from 180 to 180 , so even though 270 will work in the equation , it is beyond your domain.
But, by looking at the cosine graph , you will see that it also has an xintercept at x = 90°
so for your first one,
x = 90, 0, 90
the second part for sinx = 1/2
your answers of 30° or 150° are correct for the given domain.
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