How to Find a Derivative on the TI-84 Evo

The TI-84 Evo can find the derivative of a function at any point, and it gives you the answer as a number.

Find the derivative at a point

As an example, this finds the derivative of x² at x = 2.

  1. Press alpha, then window. That opens the FUNC shortcut menu. nDeriv(, the numerical derivative command, is item 3.
    The TI-84 Evo FUNC shortcut menu, opened with alpha and window, with nDeriv( as item 3
  2. Press 3. The derivative template appears, with the cursor in the small box under the d.
    The empty nDeriv template on the TI-84 Evo home screen, d over d with empty boxes for the variable, the function and the point
  3. Press the X key. That box asks which variable the derivative is taken with respect to. X fills in both small boxes at once, and the cursor moves into the parentheses.
    The nDeriv template reading d over dX with X equals at the end and the cursor inside the parentheses
  4. Type the function. For x², press X, then x².
    The nDeriv template with X squared typed inside the parentheses
  5. Press the right arrow, then type 2. The right arrow moves the cursor out of the parentheses into the X= box, which holds the point you want the derivative at.
    The full entry: d over dX of X squared, at X equals 2
  6. Press enter. The derivative of x² at x = 2 is 4.
    The TI-84 Evo home screen showing the derivative of X squared at X equals 2 is 4

Find the derivative on a graph

When the function is already graphed, the derivative comes straight off the graph. To follow along, press y=, type x² on the Y1 line, and press graph. (Graphing a function on the TI-84 Evo covers this part in more detail.)

The TI-84 Evo graph of Y1 equals X squared
  1. Press 2nd, then trace, and scroll down to dy/dx. The CALCULATE menu is the blue label above trace.
    The TI-84 Evo CALCULATE menu with dy/dx highlighted
  2. Press enter, then type 2. The status bar reads CALCULATING DERIVATIVE AT POINT, and the 2 goes on the X= line at the bottom.
    The TI-84 Evo graph screen asking for X, with 2 typed on the X equals line
  3. Press enter. The bottom of the screen reads dy/dx=4, the same answer as on the home screen.
    The TI-84 Evo graph of X squared with dy/dx equals 4 at X equals 2 shown at the bottom

Getting the derivative as a formula

Both ways give you the derivative at one point, as a number. The TI-84 Evo has no built-in way to get the derivative as a formula, like the 2x you get from x². CalcPlex CAS adds one: it's a program that gives derivatives as formulas.

Good to know

  • nDeriv( is also in the MATH menu. Press math and scroll down to item 8. It pastes the same template.
  • Exponents typed with ^ need one more right arrow. The first press only leaves the exponent; the second moves to the X= box. The x² key doesn't have this extra stop.
  • Trig derivatives expect radian mode. In degree mode, the derivative of sin(x) at x = 0 comes out as 0.0174532925 instead of 1. If the status bar says DEGREE, switch the angle mode back to RADIAN first.
    The derivative of sin X at X equals 0 on the TI-84 Evo: 1 in radian mode, then 0.0174532925 after switching to degree mode
  • Where there's no derivative, don't trust a number. At a sharp corner, like |x| at x = 0, OS 7.1 shows ERROR: UNDEFINED. OS 7.0 prints 0 there instead, even though no derivative exists.
    TI-84 Evo ERROR: UNDEFINED screen reading Derivative is not defined at this value