Hello eradicator2010

Welcome to Math Help Forum!

Since you've posted so many questions here, I'll get you started on each one, and leave you to (hopefully) finish off. If you simply can't see what to do next, come back to us.Divide both sides by , noting that :

Don't forget the sign when you take the square root.

Factorise:2) Solve 2sin^2x+3sinx+1 = 0

One RevolutionNow solve or .

3) Find the exact value of cos 105 (degrees) using sum and difference formulas (***I will provide if you need these***)4) Fine the exact value of sin(19π)/12 using sum and difference formulas (that is the best my PC can render pi)Now use

Use5) Find the exact value of the function tan (u+v) given that sin u = -7/25 and cos v = -4/5 (***Both U and V are in 3rd Quadrant)

and in QIII to findThen find and before using the addition formula for .

and in QIII to find

6) sin2xsinx = cosxFind exact solutions for one revolution

orIf is in QI, then and (from a 3-4-5 triangle). Now use the double-angle formulae.7) Find the exact value of sin2u cos2u and tan2u using double angle formulas and given that tan u =3/4 0<u<π/2 (again best pi I can make)

8) Use the sum to product formulas to find the exact value of the expression:

sin (5π)/4 - sin (3π)/4

Thanks again so much and it will greatly help me on Monday's test if I understood these and had correct answers!Grandad