The resultant of two forces P and Q acting at an angle $$\theta$$, is given by :

A

$$\sqrt{P^2 + Q^2 + 2PQtan\theta}$$

B

$$\sqrt{P^2 + Q^2 + 2PQsin\theta}$$

C

$$\sqrt{P^2 + Q^2 + 2PQcos\theta}$$

D

$$P^2 + Q^2 + 2PQtan\theta$$