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Question : 34 of 160
Marks:
+1,
-0
Solution:
Given,
a=2−2+, then
|a|=√4+4+1=3 Now given
|c−a|=2√2 Squaring on both sides,
|c−a|2=8⇒|c|2+|a|2−2a⋅c=8
|c|2+9−2|c|=8‌‌[∵|a|=3 and
a⋅c=|c|] ∴‌‌|c|2−2|c|+1=0 (|c|−1)2=0⇒|c|−1=0⇒|c|=1
Now, we find
(a×b)=|| (a×b)=−−2−2 ∴‌‌|a×b|=√1+4+4=3 Now, given angle between
a×b and
c is
‌.
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