AP EAMCET · Maths · Vector Algebra
Let \(A=(\alpha, 1,2 \alpha), B=(3,1,2)\) and \(\mathbf{C}=4 \hat{\mathbf{i}}-\hat{\mathbf{j}}+3 \hat{\mathbf{k}}\). If \(\mathbf{A B} \times \mathbf{C}=6 \hat{\mathbf{i}}+9 \hat{\mathbf{j}}-5 \hat{\mathbf{k}}\), then \(\alpha^2+\alpha+5=\)
- A 11
- B 7
- C 9
- D 5
Answer & Solution
Correct Answer
(B) 7
Step-by-step Solution
Detailed explanation
Given, \[ \begin{aligned} & A=(\alpha, 1,2 \alpha) \\ & B=(3,1,2) \\ & \mathbf{C}=4 \hat{\mathbf{i}}-\hat{\mathbf{j}}+3 \hat{\mathbf{k}} \end{aligned} \] and Now, \(\quad \mathbf{A B}=(3-\alpha) \hat{\mathbf{i}}+(2-2 \alpha) \hat{\mathbf{k}}\)…
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