Help Please

[HoobyDoo]

Help Please
Can someone help me with my homework?
It would be great if I could get it back within the next 10 hours.
The sooner the better though. Thanks to anyone who can do these for me.
Working out for first 3 questions would be appreciated.
Fourth question only requires multiple choice answer.

1) If sin(x) = 3/5 and sin(y) = 24/25 and, pi/2 < y < x < pi, find the value of:
a) cos(2x)
b) sin(2x)
c) sin(x-y)

2) Simplify
a) [sin(x)/sin(x)] - [cos(3x)/cos(x)]
b) sin(x)cos(x)cos(2x)

3) Prove that tan(pi/4 + x) - tan(pi/4 - x) = 2tan(2x)

4) If tan(x) = 4/3 and tan(y) = 5/12, then the value of tan(x+y) is:
Multiple Choice:
A. sin(2x)
B. cos(2x)
C. sin(4x)
D. 25/24

[ShawnD]

1) If sin(x) = 3/5 and sin(y) = 24/25 and, pi/2 < y < x < pi, find the value of:
a) cos(2x)
b) sin(2x)
c) sin(x-y)
Do a sine^-1 to 3/5 and 24/25, then add pi/2 to each of those values, then store them in your calculator, then do the functions the questions ask. The reason you add pi/2 is because the calculator will always give you the smallest angle that gives the asked value, sine(30) and sin(150) give you the same number. Type this in your calculator and you'll see what I mean
sin^-1(sin(150))
It will not give an answer of 150.

[jimmy p]

ugh....im doing that topic in maths at the moment...it sucks ***!

[BLUE_CHIP]

Use the formuli:

\sin{2A}\equiv{2}\sin{A}\cos{A}

\cos{2A}\equiv{1}-2\sin^2{A}

\sin{A-B}\equiv\sin{A}\cos{B}+\cos{A}\sin{B}

[cookiemonster]

Does this really belong in General Discussion?

cookiemonster