At what angle do the two forces (P+Q) and (P-Q) act so that the resultant is sqrt(3P^(2)+Q^(2))?

At what angle do the two forces (P+Q) and (P-Q) act so that the result

1.	At what angle do the two forces (P+Q) and (P-Q) act so that the resultant is sqrt(3P^(2)+Q^(2))?
Answer» SOLUTION :Use `R=sqrt(A^(2)+B^(2)+2ABcostheta)` `R=sqrt(3P^(2)+Q^(2)),A=P+Q,B=P-Q` Solve, `theta=60^(@)`