Sharp EL-9900 - Manual (Page 131)

16
Advanced Keyboard/TRIGONOMETRY USING THE SHARP EL-9900
Copyright © 2002, Sharp Electronics Corporation. Permission is granted to photocopy for educational use only.
9. Continue with the formula and press 2ndF SOLVER A (METHOD) and
3 (Graphic) to choose the Graphic solver.
10. To start the problem from the beginning, set A to 0. Move the cursor to
the A variable and press 2ndF EXE to see the Graphic solver variable
range screen.
11. Since area is always nonnegative, 0 could be used for BEGIN. Enter END
a value that you do not expect area to exceed, say 25. (A little bit of
estimation helps here! If your value for END is too small, increase it and
try again.)
12. Press 2ndF EXE and an autoscaled graph of the two sides of the equation
is drawn and the solution is obtained.
13. Enter Heron’s formula, A = [S(S-X)(S-Y)(S-Z)], press CL , and type the
following: ALPHA A ALPHA = 2ndF ALPHA S ( ALPHA
S – ALPHA X ) ( ALPHA S – ALPHA Y ) ( ALPHA
S – ALPHA Z ) .
14. Note that the square root symbol extends over the entire right hand side of
the equation, automatically grouping the expression under it.
15. You could enter the semiperimeter, S = (X + Y + Z), in a separate formula
in the SOLVER, but it is probably easier to find the value of S in the
computation mode and then use Heron’s formula in the SOLVER.
Press ENTER to view the variable list.
16. Use Heron's formula to find the area of a triangle with three sides of
length 7, 8, and 9. The value for S will be 12. Enter these into the solver
and press 2ndF EXE to find the area.
AREA OF A TRIANGLE
(continued)
√
1
2
√