Question

on a vector plane, prove that cos²α+cos²β+cos²γ = 1

$\displaystyle\sf\:cos^2\boldsymbol\alpha+cos^2\boldsymbol\beta+cos^2\boldsymbol\gamma=1$

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Answer 1

Answer:

a, b,y-cosins with x,y,z. axis

Then

cos2a+cos2B+cos2y=?

We know

=cos2Q=2cos²Q-1

=cos2a+coswB+cos2y

=2cos²a-1+2cosB-1+2cos²y-1

=2(cos²a+cos²B+cos2y)-3

=[[ cos ²a+cos²B+cos2y]=1]

=2(1)-3=-1

Step-by-step explanation:

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