The volume formula of trapezoid The amount of concrete used to calculate the bearing platform in the budget

The volume formula of trapezoid The amount of concrete used to calculate the bearing platform in the budget

Trapezoidal volume formula:
V = [S1 + S2 + open radical (S1 * S2)] / 3 * h
Note: V: volume; S1: upper surface area; S2: lower surface area; H: high

Does the multiplication of three vectors satisfy the commutative law of multiplication? Why?

Not satisfied! You should refer to the inner product of a vector. Here, as long as you know that the vector and the inner product of a vector are a constant, not a vector, then it's easy to understand. If for the general case, a, B and C are not perpendicular and collinear
For example: a · B · C. first calculate the first two, a · B is a constant (and not 0), then the direction of a · B · C is consistent with the direction of C vector
A · (B · C) first calculate. B · C, then. B · C is a constant (and not zero), then the direction of a · B · C is consistent with the direction of a vector
This is the most typical example

What is the multiplication of two vectors
/What is Pf1 / · / PF2 /?
Now I'm learning hyperbola. What's this multiplication?
Or not multiplication! What does it mean?

/Pf1 / · / PF2 / is not the multiplication of two vectors, but the multiplication of the modules of two vectors
The module of a vector is the length of the vector