The vectors a=3i+xj and b= 2i+j+yk are mutually perpendicular If [a] = [b], then find the value of y - Maths - Three Dimensional Geometry

Question

The vectors a=3i+xj and b= 2i+j+yk are mutually perpendicular If
[a] = [b], then find the value of y

Ajanta Trivedi · Accepted Answer

if vectors a and b are perpendicular
a·b=0
(3i+xj)·(2i+j+yk)=06+x=0⇒x=-6 
(1)and |a|=|b|⇒32+x2=22+1+y29+62=5+y29+36=y2+5y2=45-5y2=40y=±210

hope this helps you

The vectors a=3i+xj and b= 2i+j+yk are mutually perpendicular. If [a] = [b], then find the value of y.