1. ## Trig

Can somebody help me do these please.o (greater or equal to) y and (less than or equal to) 360 degrees.

1. sin(x/2)= √3/2

2. 2sin^2(x) - 7sin(x) = -3 when o (greater or equal to) x and (less than or equal to) 360 degrees.

3. and most importantly sin2(y)= 4y when o (greater or equal to) y and (less than or equal to) 360 degrees.

Thanks.

2. Originally Posted by alpina
Can somebody help me do these please.o (greater or equal to) y and (less than or equal to) 360 degrees.

1. sin(x/2)= √3/2

2. 2sin^2(x) - 7sin(x) = -3 when o (greater or equal to) x and (less than or equal to) 360 degrees.

3. and most importantly sin2(y)= 4y when o (greater or equal to) y and (less than or equal to) 360 degrees.

Thanks.
1. Let $\displaystyle y = \frac{x}{2}$. So you're solving
$\displaystyle sin(y) = \sqrt{3}/2$. Find the value of $\displaystyle y$ and then convert it back to $\displaystyle x$

2. Let $\displaystyle sin(x) = y$. So you're solving
$\displaystyle 2y^2 - 7y + 3 = 0$. Solve that for $\displaystyle y$ and then solve the equation $\displaystyle sin(x) = y$

3. I can't read your notation here. Is it $\displaystyle sin(2y)$ or $\displaystyle sin^2 y$?

3. Originally Posted by Last_Singularity
1. Let $\displaystyle y = \frac{x}{2}$. So you're solving
$\displaystyle sin(y) = \sqrt{3}/2$. Find the value of $\displaystyle y$ and then convert it back to $\displaystyle x$

2. Let $\displaystyle sin(x) = y$. So you're solving
$\displaystyle 2y^2 - 7y + 3 = 0$. Solve that for $\displaystyle y$ and then solve the equation $\displaystyle sin(x) = y$

3. I can't read your notation here. Is it $\displaystyle sin(2y)$ or $\displaystyle sin^2 y$?
thanks for your reply, and it is $\displaystyle sin(2y)$. first time doing math on computer =)), sorry.

4. So for $\displaystyle sin(2y)= 4y$, let $\displaystyle x=2y$. Then we get:
$\displaystyle sin(x) = 2x$

Use a graphing calculator of some sorts to find where $\displaystyle sin(x) - 2x = 0$

Then divide by 2 to get your value of $\displaystyle y$

5. still don't really understand how to do it right