Read the slope from a graph
Graph a function and move to a point to see dy/dx, the slope of the curve there.
The graph tools can report the slope while you stand at a point on the curve. Choose the derivative tool, type the x value you want, and the screen shows the point and dy/dx.
Classic Graphing 84
Start on the main screen: Press 2nd then mode (QUIT) to get back to the home screen. Pressing clear on a menu also backs out of it.
Press y= and enter X² as Y1.
y=X,T,θ,nx²Open the CALC menu (2nd, then trace) and choose 6, dy/dx.
2ndCALCtrace6Type the x value 1 and press enter. The screen shows the point and the slope.
1enter
You should seeX=1 Y=1 dy/dx=2
Natural Color Graphing
Start on the main screen: Press MENU then 1 to open Run-Matrix, the main calculation screen. Press EXIT to back out of a bar or screen, and SHIFT then EXIT (QUIT) to return to the app start.
Open the graph screen, enter X² and press EXE, then F6 to draw it.
MENU3X,θ,Tx²EXEF6Choose F4 (SKETCH) and then F2 for the tangent line.
F4F2Type the x value 1 and press EXE twice. The line is drawn and its slope is shown.
1EXEEXE
You should seedy/dx=2
Tips
- The x value you type must lie inside the graph window, otherwise the tool refuses it. Widen the window first if needed.
Related guides
- Find the slope of a function at a pointGet the derivative of a function at one x value as a decimal, using the built-in derivative function.
- Find the equation of a tangent lineUse the derivative to get the slope at a point, then build the line y = m(x − a) + f(a).
- Set the graph windowChoose the x and y ranges that the graph screen shows.