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Question : 38 of 120
Marks:
+1,
-0
Solution:
consider, the angle between
and
is
θ Given,
++= ⇒+=− ⇒|+|=|−| Squaring on both side, we get
⇒|+|2=|−|2 ⇒||2+2.+||2=|−|2 ⇒||2+||2+2‌ab‌cos‌θ=|−|2 ⇒(3)|2+(5)2+2(3)(5)‌cos‌θ=(7)2 ⇒30‌cos‌θ=15 ⇒cos‌θ= ⇒θ=π∕3 Hence, If
++=,||=3,||=5 and
||=7, then the angle between
and
is
π∕3
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