InterviewSolution
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InterviewSolution
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यदि दो इकाई सदिशों के बीच का कोण `theta` हो, तब `cos^(2) (theta)/(2)` का मान होगाA. `(1)/(3)|a+b|^(2)`B. `(1)/(2)|a-b|`C. `(1)/(2)|axxb|`D. `(1)/(2)|b|` |
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Answer» Correct Answer - A `therefore (a+b).(a+b)=|a|^(2)+|b|^(2)+2a.b` `=1+1+2(1)(1)cos theta` `=2+2cos theta [therefore |a|=|b|-1]` `Rightarrow |a+b|^(2)=2.2cos^(2)""(theta)/(2)` `Rightarrow cos^(2)""(theta)/(2)=(1)/(4)|a+b|^(2)` |
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