Question 307 of 379EasyMCQ
If a^,b^ and c^ are unit vectors satisfying a^−3b^+c^=0, then the angle between the vectors a^ and c^ is: Solutions · 1
Official solution
a^+c^=3b^. Squaring: ∣a^∣2+2a^⋅c^+∣c^∣2=3∣b^∣2⟹1+2a^⋅c^+1=3
\[\hat a\cdot\hat c=\frac12 \implies \theta=\frac\pi3\] Answer the question to unlock