Q) Express 3 sin x + 4 cos x in the form R cos (x-a) a is alpha
any idea i think we must change the sinx into cos x
This problem can easily be solved my comparing coefficients.
First start by stating your identity.
It is important that you understand exactly what means before you go ahead, if you don't just say.
Expand the left hand side using the compound angle formula.
compare coefficients to get
do you want to try and finish off form here ?
let me know how it goes form here.
Bobak
you forget what , it should be covered somewhere in your textbook. It means that both sides of the expression are equal for all values of x. that is to say that the left hand side is identical to the right hand side.
If two expressions are identical then the coefficients and respectively are the same. the coefficient of on the left hand side is and on he right hand side it is 3.
are you following ?
Bobak