### Derivative Calculator

Calculates the derivative of an expression specified using a simple expression syntax.
How to use   ||   Examples   ||   Other Notes

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).
• To erase the text input field, click the "Clear" button.
The text input field can accept a wide variety of expressions, including many transcendental functions, such as exponential, logarithmic, and trigonometric functions.
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 button next to the "Variable" label displays a pop-up menu which can be used to select a variable for partial derivatives. The selected variable is displayed inside the button. With a variable selected, the "Apply" button applies the derivative operator with respect to the selected variable (e.g. with "y" selected, the operator "Dy[...]" is applied). With no variable selected (the default setting), the standard operator "D[...]" is applied -- this operator is equivalent to "Dx[...]". The pop-up menu shows all available free variables.

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.