Sharp EL-9900 - Manual (Page 129)

14
Advanced Keyboard/TRIGONOMETRY USING THE SHARP EL-9900
Copyright © 2002, Sharp Electronics Corporation. Permission is granted to photocopy for educational use only.
Use the Newton Solver with the Law of Cosines.
1. Access the SOLVER with 2ndF SOLVER (or press CL twice if you are still
in the SOLVER). Press CL to delete the current equation. Return to the
Equation Solver by pressing 2ndF SOLVER A (METHOD) and
1 (Equation).
2. Next enter the Law of Cosines by pressing ALPHA Z x 2 ALPHA =
ALPHA X x 2 + ALPHA Y x 2 – 2 ALPHA X
× ALPHA
Y
× cos ALPHA θ .
3. Store this equation in the calculator.
4. Given a triangle in which two sides of lengths 13 cm and 8 cm enclose a 50°
angle. Find the length of the third side.
5. Press ENTER to view the list of variables. Press
▼ to position the cursor
on X and enter 13. Next, enter 8 for Y and 50 for
θ. Press ▲ to move the
cursor over Z and press 0 ENTER .
6. Press 2ndF EXE to solve for Z. Notice that the SOLVER has automatically
changed to the Newton Solver. You should supply an initial estimate of the
solution in the START position (0 is the default value) and a step size STEP
(.001 is the default value).
7. Press 2ndF EXE to find the solution. (If you receive an error message, try
changing the START value or increasing the STEP value.)
8. Notice the left and right sides of the equation are displayed as equal values,
and the L – R = 0.
LAW OF COSINES