Scalar Triple Product with Repeated Vector

Rarely Tested

Scalar Triple Product with Repeated Vector

$$\vec a\cdot(\vec a\times\vec b)=0$$

Usage

- Used immediately whenever the same vector occurs in the dot and cross products.

Question 1

Let $$\vec{a}$$ and $$\vec{b}$$ be two orthogonal vectors such that $$|\vec{a}| = 1$$ and $$|\vec{b}| = 2$$. If a variable vector $$\vec{x}$$ satisfies the vector equation:
$$\vec{x} + \vec{a} \times \vec{x} = \vec{b}$$
Find the value of the squared magnitude expression $$10|\vec{x}|^2$$.

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