# Very basic question on derivative notation

could B d/dt (x1 -x2) be equal to B (dot{x}1 - dot{x} 2)? Thank you!

dot{x} is supposed to be a "dot" over a x. Just a formatting problem

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## Answers and Replies

jhae2.718
Gold Member
The derivative is a linear operator, so the following properties hold:
1. $\displaystyle\frac{\text{d}}{\text{d}t}\!\left(\alpha x\right) = \alpha\dot{x}$
2. $\displaystyle\frac{\text{d}}{\text{d}t}\!\left(x_1 + x_2\right) = \dot{x}_1 + \dot{x}_2$

Thank you!