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# Trig identities question watch

1. Find all the solutions, in the interval 0<= x <2pi, of the equation (1-tanx)(2sinx+1)=0, giving each solution in terms of pi.

^ This question is from the Pearson AS maths workbook.
The identities we can use are tanx= sinx/cosx and cos2x+sin2x=1

The answers are pi/4, 5pi/4, 7pi/6 or 11pi/6

I can't seem to get the expanded equation in terms of just one trig... could I have some help with this please? I think I'll be okay finding the solutions but it's the identities that are causing me issues (as we've still not been taught this, two weeks before c2!)
2. I don't think you need to use identities for this question. Just work out the solutions for tanx=1 and sinx=-1/2 in the interval of 0<=x<2pi.

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Updated: May 9, 2015
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