Casio fx-CG50 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.
Press and choose Run-Matrix. Everything here happens on the calculation screen.
Paste the solver command with (CALC) (SolveN). The screen shows SolveN( and waits for the equation.
Type the equation as written, equals sign included: for ex, then for =, then . Press .
SolveN returns every root at once. The answer appears in braces, listing each root the calculator found, so there is no starting guess to supply and no second pass to run. Scroll the list sideways with if it is wider than the screen.
The one thing it can still miss is a root outside its search range, which by default is finite. If a graph shows a crossing that is not in the list, restrict the equation to that region by adding a range to the command, or fall back to graphing and reading the crossing directly.
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.