Question
Question: \(|\mathbf{a} \times \mathbf{b}|^{2} + (\mathbf{a}.\mathbf{b})^{2} =\)...
∣a×b∣2+(a.b)2=
A
(a×a).(b×b)
B
(a.a)(b.b)
C
∣(a×b)∣(a.b)
D
2(a.b)(a.b)
Answer
(a.a)(b.b)
Explanation
Solution
We know (a×b)2+(a.b)2=a2b2=(a.a)(b.b).
∣a×b∣2+(a.b)2=
(a×a).(b×b)
(a.a)(b.b)
∣(a×b)∣(a.b)
2(a.b)(a.b)
(a.a)(b.b)
We know (a×b)2+(a.b)2=a2b2=(a.a)(b.b).