If-xcos-ycos-zcos-0-xsin-ysin-zsin-0-and-xsec-ysec-zsec-0-then-prove-that-x-2-y-2-z-2-2-4x-2-y-2-

Question Number 157031 by PRITHWISH SEN 2 last updated on 18/Oct/21

If xcos θ + ycos \emptyset + zcos ψ = 0,

xsin θ + ysin \emptyset + zsin ψ = 0

and xsec θ + ysec \emptyset + zsec ψ = 0

then prove that

{(x^{2} + y^{2} - z^{2})}^{2} = {4 x}^{2} y^{2}