© examsiri.com
Question : 31 of 160
Marks:
+1,
-0
Solution:
a=,b= a+b=+=++ a−b=−=−−+2 Let θ be the angle between
(a+b) and
(a−b) then
cos‌θ=| (a+b).(a−b) |
| |a+b||a−b| |
=| 1(−1)+1(−1)+1(2) |
| √12+12+12√(−1)2+(−1)2+22 |
=0 ∴ θ = 90°
© examsiri.com
Go to Question: