Question

If (a ⃗ +b ⃗ ). (a ⃗ - b ⃗ )=12 and |a ⃗ |= 2 |b ⃗ |. find |a ⃗ |

Answer 1

Answer:

a^2-b^2 =12

Also, a = 2b

so, 4b^2-b^2 =12

Or, 3b^2 =12

Or, b^2=4

Or, b =2

Now, a = 2b

=2×2

=4