Last updated at May 29, 2018 by Teachoo
Misc 14 If , , are mutually perpendicular vectors of equal magnitudes, show that the vector + + is equally inclined to , and . , , are of equal magnitudes, So, = = Also, , , are mutually perpendicular to each other So, . = . = . = 0 We need to show ( + + ) is equally inclined to , , ; So, cos = + + , cos = + + , cos = + + But = = Thus, cos = cos = cos = = Therefore, ( + + ) is equally inclined to , , .
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