TI-84 Plus CE field manual for IB Math
Solving an equation numerically
Type an equation in as it is written and let the calculator solve it. The TI-84 and Nspire return one root chosen by your starting guess, so a second pass is needed for a second root; the Casio returns the whole list.
Solve ex=5x for all real x.
Open the numeric solver. Press , then once, and the highlight wraps around to the solver at the bottom of the menu; press .
Type each side into its own box: in E1 press , then to E2 and . The solver takes the equation exactly as written, so nothing needs rearranging.
Select the on-screen OK option. The equation collapses to a single line above an X= row holding your starting guess and a bound row, which you can leave alone.
Set the guess and solve. Type into X=, then select SOLVE. The solver replaces the row with a root, marked with a small square, and prints left-rt, the gap between the two sides at that value; 0 means it landed exactly.
The solver finds one root at a time. It stops at the first root it reaches from your starting guess, and a graph of the two sides shows that they cross twice, so a guess of 0 has found only the left-hand crossing. Replace the guess with and select SOLVE again to find the other root.
x=0.259 and x=2.54 to 3 s.f.
Your turn
Work each one on your calculator, then check the answer.
- 1
Solve lnx=x−2.
- 2
Solve x3=2x.
- 3
Solve cosx=x2−1, working in radians.