Find the sum of the vectors u and v it theta is the angle between them?

u=12, v=21, theta=70u=12,v=21,θ=70, the answer is 27.5, 24 degrees to vv

1 Answer
May 25, 2018

If P =P= Magnitude of vecP, Q =P,Q= Magnitude of vecQ and θ = Angle between two vectors then R = Magnitude of Resultant vecR and α = is direction of Resultant then

R=sqrt(P^2+Q^2+2PQcostheta)
alpha=tan^-1((Qsin theta)/(P+Qcostheta)), measured from vecP

Taking P as v and Q as u, we get

R=sqrt(21^2+12^2+2xx21xx12xxcos70^@)
=>R=27.5\ units

alpha=tan^-1((12\ sin 70^@)/(21+12\ cos70^@))
=>alpha=24.2^@