Biomedical Engineering Reference
In-Depth Information
Fig. A.5
Graph of a linear
equation
y
(
x
2
,y
2
)
y
(
x
1
,y
1
)
x
a
x
intercept, is the value of
y
at which the straight line intersects the
y
-axis. The
constant
b
represents the slope of the straight line and is the tangent of the angle that
the line makes with the
x
-axis. The slope of the straight line is expressed by
y
2
y
1
x
1
¼
Δ
y
slope
¼
x
¼
tan
α
:
x
2
Δ
Observe that
a
and
b
can have either positive or negative values. If
b
is positive
(negative), the straight line has a positive (negative) slope. When the straight line
passes through the origin,
a
¼
0; straight lines parallel to the
x
-axis have the same
slope
b
¼
0 and different values of
a
.
