Answers

2016-05-16T18:31:14+08:00
Solution:

2sinx cosх + 2sinx - cosx -1=0
=(2sinx cosx + 2sinx) - cosx - 1=0
factor out the one inside the bracket.
=2sinx(cosx + 1) - cosx - 1 = 0
move - cosx -1 in the right side.
=2sinx(cosx + 1) = cosx + 1
divide both sides by cosx +1.
=2sinx(cos x + 1)/cos x + 1=cosx + 1/cosx + 1
We get↓
= 2sinx = 1
divide both sides by 2.
= sinx=1/2
= x=sin⁻¹(1/2)
= x=30° or  \pi /6

Answer is 30° or  \pi /6
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