HP 40gs HP 39gs_40gs_Mastering The Graphing Calculator_English_E_F2224-90010.p - Page 105

The Solve Aplet, Equations vs. expressions, Entering the equation

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16 THE SOLVE APLET This aplet will probably rival the Function aplet as your 'most used' tool. It solves equations, finds zeros of expressions involving multiple variables, and even involving derivatives and integrals. Equations vs. expressions To ensure that we are using the same terminology, let's define our terms first. An equation includes an = sign, and can usually be solved: y = x2 ⎫ v2 = u2 + 2ad ⎪ ⎪⎪ eg. b +1= a +3 c d ⎬ ...are all equations. ⎪ ⎪ x2 − 6x + 5 = 0⎪⎭ An expression, on the other hand, does not contain an = sign. It can be evaluated or rearranged but not solved. When you enter an expression into the Solve aplet it internally puts an " = 0 " onto the end so as to convert it into an equation which can be solved. x2 − 4 ⎫ eg. b −1+1 ⎪⎪ ⎬ ... are all expressions. c ⎪ x2 − 6x + 5⎪⎭ Entering the equation Let's start by looking at the equation v2 = u2 + 2ad . This equation gives the final velocity (v) of a object as a function of the initial velocity (u), the acceleration acting on it (a) and the distance traveled (d). 105

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Equations vs. expressions
Entering the equation
16
T
HE
S
OLVE
A
PLET
This aplet will probably rival the Function aplet as your ‘most used’ tool. It solves equations, finds zeros of
expressions involving multiple variables, and even involving derivatives and integrals.
To ensure that we are using the same terminology, let's define our terms first.
An equation includes an = sign, and can usually be solved:
2
y
x
=
2
v
2
=
u
+
2
ad
eg.
…are all equations.
b
a
+
3
1
+
=
c
d
2
x
6
x
+
5
=
0
An expression, on the other hand, does not contain an = sign. It can be evaluated or rearranged but not
solved. When you enter an expression into the Solve aplet it internally puts an “ = 0 ” onto the end so as to
convert it into an equation which can be solved.
2
x
4
b
1
eg.
+
1
… are all expressions.
c
2
5
x
6
x
+
2
2
Let's start by looking at the equation
v
=
u
+
2
ad
. This equation gives
the final velocity (
v
) of a object as a function of the initial velocity (
u
), the
acceleration acting on it (
a
) and the distance traveled (
d
).
105