TI-Nspire CX II field manual for IB Math
25
All coursesEvaluating f′(a) numerically
Use the calculator's derivative template to evaluate f′(a) at a specified point.
Goal
Find f′(2.5) for f(x)=xx.
1
From the Scratchpad calculator, press → 4: Calculus → 1: Numerical Derivative at a Point.
2
Fill in the dialog, moving between fields with : Variable: x, Value: 2.5, Derivative: 1st Derivative. Select OK and press .
Scratchpad
RAD
Numerical Derivative at a Point
Variable:x▶
Value:2.5▶
Derivative:1st Derivative▶
OKCancel
3
The d/dx(▯)|x=2.5 template lands on the entry line with the cursor in the expression box. Type for the function.
4
Press to evaluate.
Scratchpad
RAD
dxd(xx)∣∣∣x=2.5
18.937
Result
f′(2.5)≈18.9.
Your turn
Work each one on your calculator, then check the answer.
- 1
Find f′(1.8) for f(x)=x2x.
- 2
Find f′(4) for f(x)=(lnx)x.
- 3
Find f′(3) for f(x)=x1/x.