Question

sin2x-sinx=0

Answer 1

what should we do ? prove it or what ?

Answer 2

To find the zeroes, you may factor out a "sinx" from both go get:\[sinx(sinx-1)=0\]
This tells us that the values that make y zero are when sinx=0, and sinx=1 (made sinx alone inside the parenthesis).
From our unit circle, sinx=0 at 0 and 2pi.
Sinx=1 at pi/2 and 3pi/2.
If you need more elaboration, feel free to ask.

Answer 3

i think sin2x = 2sinxcosx not 2sinx

Answer 4

sin2x-sinx=0
2sinxcosx-sinx=0
sinx(2cosx-1)=0
u can find the value of x
sinx=0
2cosx-1=0

Answer 5

Mmm, indeed, depends if she meant sin^2(x) or sin(2x)...I believe you're correct in the interpretation, however.