Dawnbridge

TI-Nspire CX II field manual for IB Math

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25

Evaluating f(a) numerically

All courses

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: Calculus1: 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. 1

    Find f(1.8) for f(x)=x2x.

  2. 2

    Find f(4) for f(x)=(lnx)x.

  3. 3

    Find f(3) for f(x)=x1/x.