Let , , and . The value of is:
- (A)-106.5
- (B)-112.5
- (C)-118.5✓ Correct
- (D)-99.5
Answer: (C)
Solution
First pin down the angle between the vectors. From , we have , so , which means . Now expand the product, .
JEE Main · 2019 · 08 Apr 2019 · Shift 2 · Single correct option