Question

cosx cos (pi/7)+sinx sin (pi/7)= -sqrt2/2


x can equal:

Answer 1

\[5\pi/4+\pi/7+2n \pi\]

Answer 2

\[7\pi/4+\pi/7+2n \pi\]

Answer 3

wat is rhs?

Answer 4

\[3\pi/4+\pi/7+2n \pi\]

Answer 5

\[\cos x \cos (\pi/7)+\sin xsin(\pi/7)=\cos (x-\pi/7)=-\sqrt{2}/2\]

Answer 6

1 nd 3

Answer 7

or \[\pi/4+\pi/7+2n \pi\]

Answer 8

corrected

Answer 9

which of the 4 equations do you think is correct? there can be more than 1

Answer 10

1st nd 3rd

Answer 11

thank youu :)