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If alpha, beta , gamma are direction-an...

If `alpha, beta , gamma ` are direction-angles of a line, prove that
(i) `cos2alpha + cos 2 beta +cos2 gamma+ 1 = 0`.
(ii) `cos 2 alpha + cos 2 beta + cos 2 gamma = -1`.

Text Solution

Verified by Experts

The correct Answer is:
(i) cos`2alpha` + cos `2 beta` + 1 = `theta`.
which is true.
(ii) cos `2 alpha `+ cos `2 beta = cos 2 gamma ` = -1. which is also true.
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