If →a=x^i−y^j and →b=y^i+x^j,∣∣∣→a×→b∣∣∣=5, then the locus of (x,y) is :
→a×→b=∣∣ ∣ ∣∣^i^j^kx−y0yx0∣∣ ∣ ∣∣=0^i+0^j+(x2+y2)^k ∣∣∣→a×→b∣∣∣=x2+y2 x2+y2=5 It is an equation of a circle.