Direction of P,v^1=±∣A×B∣A×B=±3i^−j^+k^
Direction of Q,v^2=±∣A×C∣A×C=±22k^=±k^
Angle between v^1 and v^2,
∣v^1∣∣v^2∣v^1⋅v^2=(1)(1)±31=±31
⇒x=3
Three particles P,Q and R are moving along the vectors A=i^+j^,B=j^+k^ and C=−i^+j^, respectively. They strike on a point and start to move in different directions. Now particle P is moving normal to the plane which contains vector A and B. Similarly particle Q is moving normal to the plane which contains vector A and C. The angle between the direction of motion of P and Q is cos−1(x1). Then the value of x is .
Held on 22 Jul 2021 · Verified 1 Jul 2026.
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