# Trig - Finding Angles

• Jun 25th 2008, 05:01 PM
Nick87
Trig - Finding Angles
Having trouble with my Trig these days. I was wondering if you could help me out?

Q. If Angle B is acute and TanB = $\frac 3{4}$

Find sinB, cosB, sin2B and tan2B

- - -

Also, could anyone help me with another solving for 0 ≤ x ≤ 360 question?

Q. $4 - sinx = 4cos^2x$

Methods would be great. Thanks! Always appreciative of response (Rofl)
• Jun 25th 2008, 05:14 PM
Quote:

Q. If Angle B is acute and TanB = http://www.mathhelpforum.com/math-he...2ac0d935-1.gif

Find sinB, cosB, sin2B and tan2B
using $\tan = \frac{opposite}{adjacent}$ we can draw a right angle triangle like this:

Attachment 6973

can you continue?

For the last 2 you may like to use these:
$\sin(2x) = 2\sin(x)\cos(x)$
$\cos(2x) = \cos^2(x)-sin^2(x)$
There are other formulas you might know but these are the ones I have memorised.

Quote:

Also, could anyone help me with another solving for 0 ≤ x ≤ 360 question?

Q. http://www.mathhelpforum.com/math-he...5b52d117-1.gif
The first step uses $\sin^2(x)+\cos^2(x)=1$