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If P + Q = R and P - Q = S, prove that R...

If P + Q = R and P - Q = S, prove that `R^2 + S^2 = 2(P^2 + Q^2)`

Text Solution

Verified by Experts

`R^2 = P^2 Q^2 + 2PQ cos theta …..(i)`
`S^2 = P^2 + Q^2 - 2PQ cos theta (i)`
Adding these two equations we get,
`R^2 + S^2 = 2(P^2 +Q^2)`
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DC PANDEY ENGLISH-VECTORS-Subjective
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