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Need solution for RD sharma maths class 12 chapter 24 vector or cross product Exercise Multiple choice questions question 16 maths textbook solution

Answers (1)

Answer: 16

Given: \left | \overrightarrow{a} \right |=10 & \left | \overrightarrow{b} \right |=2and \overrightarrow{a}.\overrightarrow{b} =12

Hint: Using the result \left | \overrightarrow{a}\times \overrightarrow{b} \right |^{2}=\left | \overrightarrow{a} \right |^{2}\left |\overrightarrow{b} \right |^{2}-\left | \overrightarrow{a}.\overrightarrow{b} \right |^{2}

Explanation:

              Here    \left | \overrightarrow{a} \right |=10 & \left | \overrightarrow{b} \right |=2and \overrightarrow{a}.\overrightarrow{b} =12

We know,

              \begin{aligned} |\vec{a} \times \vec{b}|^{2} &=|\vec{a}|^{2}|\vec{b}|^{2}-|\vec{a} \cdot \vec{b}|^{2} \\ &=(10)^{2}(2)^{2}-(12)^{2} \\ &=100 \times 4-144 \\ &=400-144 \\ &=256 \\ |\vec{a} \times \vec{b}|^{2} &=256 \\ |\vec{a} \times \vec{b}| &=\sqrt{256}=16 \\ |\vec{a} \times \vec{b}| &=16 \end{aligned}

          

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