Question

If P+Q=R and |P|=|Q|=√3 and |R|=3, then the angle between P and Q is _______ ?

Answer 1

Answer:

Explanation:

⇒P+Q=R,

⇒{lPl=√3, lQl=√3}, ⇒ Q We have to calculate,

⇒R=3,

⇒lP+Ql=lRl,

⇒√lPl²+lQl²+2lPl lQl cosθ,

⇒3=√(√3)²+(√3)²+2(√3)(√3)cosθ,

⇒Squaring both sides :

⇒9=3+3+6cosθ,

⇒cosθ = 1/2⇒θ= 60° or π/3,

And,

∴ P+Q=R and |P|=|Q|=√3 and |R|=3, then the angle between P and Q is 60° or π/3.

Hope it helps.