# Math Help - Trigometric equations.

1. ## Trigometric equations.

Stuck on three problems

I tried to factor these bottom 2 but, nothing is adding up. An im lost what to do now.

2. Originally Posted by S2Krazy
Stuck on three problems

I tried to factor these bottom 2 but, nothing is adding up. An im lost what to do now.

This looks like part of an on-line test that counts towards assessment. pm me with an explanation if this is not the case.

MHF policy is to not knowingly help with such questions. Thread closed.

3. Originally Posted by mr fantastic
This looks like part of an on-line test that counts towards assessment. pm me with an explanation if this is not the case.

MHF policy is to not knowingly help with such questions. Thread closed.
OK, it appears this is homework that doesn't count towards assessment. Here is a start:

Solve $4u^2 - 7u - 1 = 0$ and $u^2 - 8u + 3 = 0$ using the quadratic formula and then use the solutions that lie between 1 and -1 to construct simple trig equations. Solve those equations.

If you need more help, please show all your work and say exactly where you're stuck.

4. using the quad form i believe made it more confusing!. for that first problem 4sin^2.. i got

-7 plus minus root 65 /8 is that correct so far? then after this what do i do?

5. Originally Posted by S2Krazy
using the quad form i believe made it more confusing!. for that first problem 4sin^2.. i got

-7 plus minus root 65 /8 is that correct so far? then after this what do i do?
It's not -7, it's +7 (b = -7 so -b = 7).

Now you solve $\sin (2 \theta) = \frac{7 - \sqrt{65}}{8}$ and you should already have met problems like this.