me gana hadanne kohomada?

[VSGM]

1. Deduce that :-

cos^3 Q + cos^3 (Q+60) + cos^3 (Q+120) = 3/2cos(Q+60) + 1/4cos3Q

2. if a = Sin Q + cos X and b = Cos Q + Cos X, prove that;

Cos ( Q-X) = 2ab/ a^2 + b^2

pls pls can any one help me

 

[VSGM]

kawruth nadda?

 

[VSGM]

BUMP

 

[knightshifters]

Dude, this must be AL math. Its been ages so i have forgotten the expansions for cos^3Y and cos(A+B). But ill tell you how to solve. For your first prob, use the expansion of former. For the second, use the latter and after expanding, substitute with given equations. Should not be too hard.

 

[knightshifters]

If its cos3Y taught as a standard expansion and not cos^3Y, then derive a formula for the latter using former. Dont let yourself confused wit (x+60) and (x+120) forms. First sub them with variables like E and F and do the simplification

 

[windows8]

owa AL kalenam pana dagena kara dan mathaka naha malli

 

[h_abeysinghe]

oh danne nae bt onna magen BUMP ekak