Q28 of 177 Page 24

A unit vector makes angles respectively and a acute angle θ with Find θ.

The sum of squares of direction cosines of a vector is 1.

Let the angles made by vector be α, β, θ. Then, we get


cos2α+cos2β+cos2θ=1


Given that , we have to calculate θ



⇒ (Since θ is acute)


Hence,


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