can anybody help?

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- Dec 9th 2012, 04:02 AMtautvydukssimplify and proof that answer is this
can anybody help?

Attachment 26152 - Dec 9th 2012, 04:09 AMtopsquarkRe: simplify and proof that answer is this
- Dec 9th 2012, 04:10 AMMarkFLRe: simplify and proof that answer is this
How do you begin with an expression and end with an equation?

- Dec 9th 2012, 04:11 AMtautvyduksRe: simplify and proof that answer is this
but what i should do with 1/2sin(alpha)

- Dec 9th 2012, 04:14 AMMarkFLRe: simplify and proof that answer is this
Subtract it from the expression

**topsquark**gave you after you have simplified it. - Dec 9th 2012, 04:16 AMtopsquarkRe: simplify and proof that answer is this
For the second problem, note that , so we have

Multiply out the RHS and use , then solve for sin(x).

You will get

Note that there will be*four*solutions to this.

-Dan

Wow. Lots of posting going on in this thread! - Dec 9th 2012, 04:17 AMtautvyduksRe: simplify and proof that answer is this
x

- Dec 9th 2012, 04:27 AMtautvyduksRe: simplify and proof that answer is this
ok, thanks i did that but what i have to do with -1/2sin(alpha)? im bad at maths sorry

- Dec 9th 2012, 04:30 AMtautvyduksRe: simplify and proof that answer is this
- Dec 9th 2012, 04:42 AMMarkFLRe: simplify and proof that answer is this
The second problem is:

This is not an identity to prove, but an equation to solve.

Using the double-angle identity for sine provided by**topsquark**, we have:

You will find 4 solutions on the interval . If you are not restricted to an interval, then you will have an infinite number of solutions, which is easily expressed as the integral multiple of an angle. - Dec 9th 2012, 05:36 AMtautvyduksRe: simplify and proof that answer is this
i need to suplify left side of this and get the right side.. not to solve X...

- Dec 9th 2012, 05:41 AMMarkFLRe: simplify and proof that answer is this
It is not an identity. It is only true for certain values of

*x*. - Dec 9th 2012, 05:54 AMtautvyduksRe: simplify and proof that answer is this
ohhh it`s imposibble tu supplify it am i right?

- Dec 9th 2012, 06:19 AMMarkFLRe: simplify and proof that answer is this
It is impossible to take the left side and get the right, yes.

- Dec 9th 2012, 06:35 AMtautvyduksRe: simplify and proof that answer is this
oh thanks. and can you help with the 1st one?