# Prove the Following Vector Identities Part 1

#### bugatti79

What you wrote it correct.
So I just evaulate this, tidy it up and show that it equals the RHS of question?

Cheers

#### I like Serena

Homework Helper
Uhh... what you have is the RHS of the question.

What you need to do is take the LHS of the question, evaluate it, and show that it is equal to what you just wrote (aka the RHS of the question).

#### bugatti79

Uhh... what you have is the RHS of the question.

What you need to do is take the LHS of the question, evaluate it, and show that it is equal to what you just wrote (aka the RHS of the question).
Hmm...How would you evaluate the LHS? I thought the RHS matrix could be simplified further to arrive at something that resembles the LHS :-)

#### Mark44

Mentor
The left side is the derivative of the cross product u(t) X v(t). Calculate the cross product, and then take the derivative. If that turns out to be equal to what you have in post #24, you have shown that d/dt(u(t) X v(t)) = u'(t) X v(t) + u(t) X v'(t).

#### bugatti79

The left side is the derivative of the cross product u(t) X v(t). Calculate the cross product, and then take the derivative. If that turns out to be equal to what you have in post #24, you have shown that d/dt(u(t) X v(t)) = u'(t) X v(t) + u(t) X v'(t).
Thank you Mark and I.L.S

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