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Question : 34 of 160
Marks:
+1,
-0
Solution:
a×(b×c)=‌b ⇒‌‌(a⋅c)b−(a⋅b)c=‌b On comparing both sides, we get;
a⋅c=‌ and
a⋅b=0 ⇒|a||c|cos‌θ2=‌‌‌{∵|a|=|b|=|c|=1} ⇒‌‌cos‌θ2=‌ ⇒‌‌θ2=60∘ |a||b|cos‌θ1=0 ⇒‌‌cos‌θ1=0‌‌(∵|a|=|b|=|c|=1) ⇒‌‌θ1=90∘ ∴‌‌θ1+θ2=60∘+90∘=150∘
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