If two vectors A → and B → having equal magnitude R are inclined at an angle θ , then

If two vectors A→ and B→ having equal magnitude R are inclined at an angle θ, then
  1. A→−B→=2Rsinθ2
  2. A→+B→=2Rsinθ2
  3. A→+B→=2Rcosθ2
  4. A→−B→=2Rcosθ2

Solution

The magnitude of resultant vector A→+B→ is given by, 

R'=A2+B2+2ABcosθ

Here A=B=R

Then R'=R2+R2+2R2cosθ

=R21+cosθ

=2R2cos2θ2

=2Rcosθ2

Asked in: JEE Main 2024 (31 Jan Shift 2)

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