##### How to use
Enter an expression for evaluation and computation into the text input field.

Example: cos x

Apply the derivative operator "D[...]" -- there are two ways to do this:

• Click the "Apply" button to apply the derivative operator "D[...]" to the entire expression previously entered into the text input field; or
• Include the derivative operator "D[...]" in the expression when entering it into the text input field.

Example: D[cos x]

Click the "Compute" button. The result of one derivative evaluation step will be entered back into the text input field.

If necessary, repeat the previous step to continue evaluating the derivative.

Example: D[x cos(x2)], takes three clicks

For partial derivatives, use the partial derivative operators "Dx[...]", "Dy[...]", "Dz[...]", etc. There are two ways to do this:

• Click the button next to the "Variable:" label and select a variable from the pop-up menu (the variable name will be displayed in the button), and click the "Apply" button; or
• Include the partial derivative operator "Dx[...]", "Dy[...]", etc., in the expression when entering it into the text input field.

Example: Dy[cos(xy2)]

To erase the text input field, click the "Clear" button.

##### Examples
Basic rules:

Derivative of x: D[x] = 1

Constant Multiple: D[2x] = 2

Exponential: D[ex] = ex

Cosine: D[cos x] = -sin x

Multiple steps:

Product Rule: D[x cos x] (two steps)

Power Rule: D[(cos x)3] (two steps)

Chain Rule: D[cos(x2)] (two steps)

##### Other Notes
The label under the text input field indicates the derivative rule used for evaluation each time the "Compute" button is clicked.

The applet can also compute multiple derivatives --  for example, D[D[cos x]] (the second derivative of cos x), which requires three steps to complete.