Download Casio fx

Casio fx-3650P
Cosine Formula
B
Given the two sides a, b and their included angle C
of a triangle, then the third side c can be found by
c
a
c  a 2  b 2  2ab cos C .
A
C
b
Programming Guide
Programming steps
Remarks
Switch to Program Edit
Mode.
1
1
?
Select P1 for programming.

A : ?
A
 B
B
2
: ?

C
:
2 A B
Store input data a, b, c in
memories A, B, C.
C Apply Cosine Formula.
Exit Program Edit Mode
and return to Run Mode.
Running the program
The table below summarizes how you may use the program to solve the following
problem.
● In △ABC, if a = 2, b = 2, C = 60°, find c.
Keying steps
Display
Remarks
A?
1
*
Select P1. * stands for the
value stored in memory.
B?
2
*
C?
2
Follow the input prompts of
the calculator.
*
(A2+B2-2ABc
60
2
0
Answer. You can continue
your input for the next
problem by pressing
.
Exit.
The same program can be used to find a and b. Always enter the adjacent sides as
inputs A and B and the included angle as input C.
Further Practice
Now you can try to solve the following questions using the program. Check whether
you can get the correct results.
Adjacent Sides
Included Angle
Input (A; B; C)
Opposite side Output
3, 4
50
3; 4; 50
3.094 (3 d.p.)
3.094042238
1, 2
1, 3
45
1; 2 ; 45
1; 3 ; 90
1
1
2
2
90