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## Homework Statement

A = A(t), B = constant

[tex]\frac{d}{dt} \left[A \cdot (\dot{A} \times B) \right] = \frac{d}{dt} \left[A \cdot (\ddot{A} \times B) \right] [/tex]

## The Attempt at a Solution

In Einstein notation I get

[tex]LHS = \frac{d}{dt} \left [ A_i (\dot{A} \times B)_i \right] = \frac{d}{dt} \left [ \epsilon_{ilm} A_i \dot{A}_l B_m \right] = \epsilon_{ilm} B_m \frac{d}{dt} \left [A_i \dot{A}_l \right] [/tex]

Is this right so far? Product rule on A and A-dot from here?

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