Hey guys, I just got it.
My formula is cos(x+or-y)=cos(x)cos(y)+or-sin(x)sin(y)
So I assumed that if you were adding angles you'd use addition on the left hand side also, I tried using minus and it worked.. Is that right or is the test wrong?
Hi guys, I thought I knew how to do these but I've done this question over and over on an online test that you can self check answers and I can't get the right answer.
Here's the situation:
sin(x)=3/4 1st quadrant
sin(y)=1/2 2nd quadrant
As, cos(x)=sqrt(1-sin^2(x))
cos(x) =sqrt(7)/(4)
cos(y)=sqrt(-3)/(2)
cos(x+y)=cos(x)cos(y)+sin(x)sin(y)
and I get OVER AND OVER this answer: 3/8-sqrt(21)/8
I spent about half an hour trying to use LaTex to no avail. Sorry.
If someone can grind out something different and post that'd be wonderful.
Hey guys, I just got it.
My formula is cos(x+or-y)=cos(x)cos(y)+or-sin(x)sin(y)
So I assumed that if you were adding angles you'd use addition on the left hand side also, I tried using minus and it worked.. Is that right or is the test wrong?