Answer:
\(\cdot\) (written as \cdot) is the centered dot used for multiplication or the dot (scalar) product. “Idot” usually means \( \dot{I} \), i.e. I with a dot above it, which denotes the time derivative \( \dfrac{dI}{dt} \).
Explanation:
- \(\cdot\): in arithmetic/algebra it denotes multiplication, e.g. \(3\cdot4=12\). In vector calculus it denotes the dot (scalar) product: for vectors \(\mathbf{a},\mathbf{b}\), \(\mathbf{a}\cdot\mathbf{b}=a_xb_x+a_yb_y+a_zb_z\).
- \(\dot{I}\): Newton (dot) notation for derivatives with respect to time. \(\dot{I}=\dfrac{dI}{dt}\). Example: if \(I(t)=5t^2\), then \(\dot{I}=10t\).
(If you meant something else by “Idot” — e.g. a dotted lowercase \(i\) or a LaTeX command — tell me and I’ll clarify.)