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3 votes
Solve the equation: Sin2x - Sinx = 0

User Zskalnik
by
7.0k points

1 Answer

5 votes
We know that sin2x=2sinxcosx
(search the net for proof if you wish)

So the original equation becomes

2sinxcosx-sinx=0
The two terms both have sinx that can be taken out to get:

sinx(2cosx-1)=0
This is true if sinx=0 or 2cosx-1=0 , rewritten: cosx=1/2

sinx=0 than x=2kπ
cosx=1/2 than x=π/3+2kπ
where k is an integer

User Robertwb
by
6.3k points
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