## Resolving vectors into their components

I find students encounter difficulties in resolving vectors into the components, especially when the axis is tilted or rotated. The following are some steps which I find useful to emphasize to them:

1. Draw the axis. Without drawing the axis, it is difficult to find the components on the axis. So always draw the axis.
2. Draw a rectangle with a diagonal line, and follow this criteria: (a) The vector we want to resolve is the diagonal line, (b) The sides of the rectangle must coincide with the axis.
3. Indicate the known angle.
4. Use TOA CAH SOH to determine which trigonometric functions to use.

## Identity divergence of a curl

This is an interesting identity: the divergence of a curl is zero.

$\nabla \cdot (\nabla \times \mathbf{B}) = 0$

We can get a continuity equation from the Maxwell equation relating the charge density and the current density using this equation.

## Write Mathematical Expressions on your Blog at WordPress

This is cool, you can type math expression in Wordpres. Check this link.

let me try it
$H\Psi=E\Psi$

$i\hbar\frac{\partial}{\partial t}\left|\Psi(t)\right>=H\left|\Psi(t)\right>$