Derive parallelogram law by using components Share with your friends Share 0 Shivam Kumar answered this Dear Student, Given two vectors P→ and Q→ inclined at an angle θ. Let their resultantvector R→ makes an angle α to the direction of vector P→ as shown in the diagram.We are given OA→ =P→, AC→ =Q→ and AD=Q→ cosθ, CD=Q→ sinθNow from right angled triangle ∆ODC , we get, OC=R=OD2+DC2 =OA+AD2+DC2 or R=P+Q cosθ2+Q sinθ2 =P2+Q2 cos2θ+2PQ cosθ+Q2 sin2θ or R = P2+Q2 +2PQ cosθ and direction of resultant vector is given by, tanα=Q sinθP+Q cosθor α = tan-1Q sinθP+Q cosθ Regards, 1 View Full Answer
