Question

If |a-b| = |a| = |b|, then what is the angle between a and b?

VECTORS

Answer 1

we know

magnitude of difference of vectors=(a^2+b^2-2abcos∅)^1/2

here

it is given that

|a|=|b|=|a-b|

so, putting a=b,we will get

|a-a|=(a^2+a^2-2a^2cos∅)

0=2a^2(1-cos∅)

cos∅=1

cos∅=cos0

∅=0°

Hence the angle between them will be 0