Question

R = P2 + Q2 + 2PQ cos​

Answer 1

Answer:

Explanation:

Let  two vector  P and Q have same initial point and they do not meet each other .Both vector have different direction and angle between the vector is $\Theta$ .Let a vector R which join the vector P and Q.

We can find out the value of R  in terms of P ,Q and $\Theta$.

$R^{2}=P^{2}+Q^{2}+2PQcos\Theta$

where R is the resultant vector

$\sqrt{R^{2}}=\sqrt{P^{2}+Q^{2}+2PQcos\Theta$

$R=\sqrt{P^{2}+Q^{2}+2PQcos\Theta$

here R defined only magnitude