The fundamental identities that are useful are
Pythagorean relations: cos^2 x + sin^2 x = 1
Inverse trigo identity: cos x = 1/secx
Applying the pythagorean theorem, the equation would be:
7sec^2 x(cos^2 x)
Then applying the inverse trigo identity, the answer would be 7.
Thus, the final answer is 7.
