# Preparing for next year 3

• Dec 12th 2010, 08:24 PM
jonoe
Preparing for next year 3
Hi,

I've asked for a list of questions from a teacher to do over the holidays. I'm struggling to use the text book to help me.

Could someone provide HOW to do these questions, as I just want to get an idea of what I'm getting next year.

Thanks.

5. Find the exact solutions of $sin(4x) = cos(2x), for 0<=x<=pi$

6. Given that $tan(2x) = (4sqrt(2))/7$ where $x$ is an element of $[0,pi/4)$ find the exact value of $sinx$
• Dec 12th 2010, 11:46 PM
mr fantastic
Quote:

Originally Posted by jonoe
Hi,

I've asked for a list of questions from a teacher to do over the holidays. I'm struggling to use the text book to help me.

Could someone provide HOW to do these questions, as I just want to get an idea of what I'm getting next year.

Thanks.

5. Find the exact solutions of $sin(4x) = cos(2x), for 0<=x<=pi$

6. Given that $tan(2x) = (4sqrt(2))/7$ where $x$ is an element of $[0,pi/4)$ find the exact value of $sinx$

5. Substitute sin(4x) = 2 sin(2x) cos(2x), re-arrange, factorise, use the null factor law and get two simple trig equations to solve.

6. Get tan(x) using double angle formula. Use the value of tan(x) to get value of sin(x).