Casio fx-7400G PLUS Booklet

– 21 –
Determine the slopes of the graphs shown below.
k Back to Ohm’s Law
Getting back to Ohm’s Law, consider the relationship I = E/R. Compare this with the y = ax
proportional expression we discussed on the previous page.
If we substitute I for y and E for x, a becomes 1/R .
This results in the proportional expression I = 1/R E. If R is constant, then I is proportional
to E. In other words, doubling or tripling the voltage value also causes the current value to
double or triple.
Expression 1
4 = a  4
a = 1
Therefore: y = x
Expression 2
2 = a  3
a = 2 / 3
Therefore: y = 2x / 3
EE-2 Ohm’s Law
y
0123456 x7
1
2
3
4
12

Casio fx-7400G PLUS Specifications

General

Model	fx-7400G PLUS
Category	Graphing Calculator
Display	LCD
Display Lines	8
Display Characters	21
Memory	28 KB
Power Supply	Battery
Programming	Yes
Graphing	Yes
Equation Solver	Yes
Statistical Functions	Yes
Connectivity	No
Battery	AAA x 4