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Question : 140 of 150
Marks:
+1,
-0
Solution:
v=×=|a||b|sin‌θ‌=sin‌θ‌ Where,
θ is the angle between
a and
b.[∵|a|=1=|b|] ∴[V]=sin‌θ Now,
u=−(.)=−(cos‌θ) ⇒|u|2=(−(cos‌θ)) .(−cos‌θ)) =a2+cos2θb2−2‌cos‌θ‌a‌b [|a|2=|b|2=|a||b|=1]=1+cos2θ−2cos2θ =1−cos2θ=sin2θ ∴|u|=sin‌θ Thus
|v|=|u|
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