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Question : 2 of 160
Marks:
+1,
-0
Solution:
Given, condition is
++= . . . (i)
and
,, are the unit vectors.
Then
||=||=||=1Let the angle between
and
is
θ.
Now, from Eq. (i)
++‌=0(+)‌=−Squaring on both sides
‌(+)2=()2‌‌[∵()2=||2]‌⇒()2+()2+2()⋅()=||2‌⇒‌‌||2+||2+2⋅=||2‌⇒‌‌1+1+2{||||cos‌θ}=1‌[∵⋅=||||cos‌θ]‌⇒‌‌2{1⋅1⋅cos‌θ}=−1‌⇒‌‌cos‌θ=‌‌⇒‌‌cos‌θ=cos(‌)‌⇒‌‌θ=‌‌
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