Question

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Answer 1

Direction cosines of a vector ai + bj + ck are,

$(\frac{a}{\sqrt{a^2+b^2+c^2} },\frac{b}{\sqrt{a^2+b^2+c^2}},\frac{c}{\sqrt{a^2+b^2+c^2}} )$.

Given vector i - j + 5k.

Therefore its direction cosines are $(\frac{1}{\sqrt{1^2+(-1)^2+5^2} },\frac{-1}{\sqrt{1^2+(-1)^2+5^2}},\frac{5}{\sqrt{1^2+(-1)^2+5^2}})$.

$(\frac{1}{\sqrt{27} } ,\frac{-1}{\sqrt{27} } ,\frac{5}{\sqrt{27} })$.