Two forces P and 2P are acting at an angle theta. If thesquare of the resultant of them is equal to half of the sum of the squares of their magnitude then theta is

Two forces P and 2P are acting at an angle theta. If thesquare of the

1.	Two forces P and 2P are acting at an angle theta. If thesquare of the resultant of them is equal to half of the sum of the squares of their magnitude then theta is
Answer» `sin^(-1) ((5)/(8))` `COS^(-1) ((-5)/(8))` `cos^(-1) ((8)/(5))` `0^(@)` Answer :B