My question states: cos(3x)+cos(x)=0
I got two answer pi/2 and pi/4 but there are supposed to be more, can you show me how to get all the answers?
Recall thatOriginally Posted by aussiekid90
This is a quadratic. Let y = cos(x):
Using the quadratic formula I get:
Now. so we need to take the positive sign. As it happens the result doesn't seem to have a nice form, so:
. Since this angle is second quadrant, we also get an angle .