I have a precalculus test tomorrow and I've been studying nonstop for the past few days but I've been struggling because it has been 8 years since the last math class I have taken.
My question is about half-angle formulas,
My professor taught us that they are:
Sin(Theta/2)= +/- SquareRoot of (1/2 - 1/2*cos(Theta))
Cos(Theta/2)= +/- SquareRoot of (1/2 - 1/2*cos(Theta))
but my text book teaches me that they are:
Sin(Theta/2)= +/- SquareRoot of ((1-cosTheta)/2)
Cos(Theta/2)= +/- SquareRoot of ((1+cos(Theta)/2)
I understand that they are the same but is there some mental trick when using one over the other?
1 answer
doesn't matter - they are the same. Use whichever one is easier for you to remember.
9 answers