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Let a and b be unit vectors inclined at an angle 2alpha(0lealphalepi) each other, then (a+b) lt 1, if |
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Answer» `ALPHA=(pi)/(2)` ` IMPLIES SQRT(1+12cos 2 alpha )lt 1` ` implies sqrt(2(1+cos 2 alpha ))lt 1` `implies sqrt(4 cos^(2) alpha )lt 1` `implies | cosalpha |lt (1)/(2)` `implies (pi)/(3)lt alpha lt (2pi)/(3) [ :'0 le alpha le pi ]` |
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