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# A level maths Trig watch

1. Can someone come lease tell me where I have gone wrong here because this is obviously not going to work out.
2. (Original post by Hannahkisley)

Can someone come lease tell me where I have gone wrong here because this is obviously not going to work out.
you can replace 1 - cos2x with sin2x

then you have sin2x = 2sinx

so sin2x - 2sinx = 0

now you should factorise the LHS
3. (Original post by Hannahkisley)

Can someone come lease tell me where I have gone wrong here because this is obviously not going to work out.
If the original question was

then you should factorise instead of dividing by . Dividing an equation by a trig function will often mean you lose solutions so it should be avoided.

For future posts please try to make your images clearer and post them the correct way up.
4. sin^2(x) is not 2sin(x). Rearrange the identity cos^2(x) + sin^2(x) = 1.
5. (Original post by Edgemaster)
sin^2(x) is not 2sin(x). Rearrange the identity cos^2(x) + sin^2(x) = 1.
That’s what I did and I got sin^2 x = 1-cos^2 x so I replaced 1-cos^2 x in the initial equation with sin^2 x to get sin^2 x = sin x

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