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How to find the slope at a point on a graph on a TI-84 Plus CE, TI-84 Plus or TI-83 Plus

By E-Code · updated

Graph the function, press 2nd CALC (above TRACE) and 6 for dy/dx, type the X value (or move there with ◀ ▶) and press ENTER. The slope at that point appears as dy/dx: for X² at X = 3 it is 6.

Before you start

Type the function into the Y= editor first: this guide uses Y1 = X² (Y=, X,T,θ,n, x², then 2nd QUIT).

Y= X,T,θ,n X² 2nd MODE

Step by step

  1. Draw the graph. GRAPH Press GRAPH. Y1 = X² is already typed in for you.
  2. Open CALC. 2nd TRACE Press 2nd, then TRACE. CALC (written above TRACE) holds the graph tools.
  3. Pick dy/dx. 6 Press 6 for dy/dx, the slope of the graph at a point.
  4. Pick the point. 3 Type 3: the slope at X = 3. You can also move there with ◀ ▶.
  5. Get the slope. ENTER Press ENTER.
  6. Read the slope. dy/dx = 6: at X = 3 the curve Y = X² climbs 6 for every 1 across. The exact derivative, 2X, gives 6 too.

What the screen shows

dy/dx = 6: at X = 3 the curve Y = X² climbs 6 for every 1 across. The exact derivative, 2X, gives 6 too.

Look for dy/dx=6 on the screen.

Try it with the keys lit up

This guide is one of E-Code's Learn lessons. Open it on E-Code's TI-84 calculator and each key lights up in turn as you press it.

Try “Find the slope at a point on a graph” on the TI-84 calculator

Related

Math programs for the TI-84 Plus CE:

All TI-84 calculus guides · All TI-84 guides · All calculator guides