Calculus - P.2 Linear Models and Rates of Change Flashcards
Possibilities for slope of a line
- m>0 -> rises to the right
- m<0 -> rises to the left
- m is undefined -> n/0 -> vertical
- m=0 -> horizontal
Slope
Rate of change, rise/run, steepness, slant, tilt
Formula:
y2-y1/x2-X1
Note 1: Any two collinear points will have the same slope
Note 2: Ratio: Dy/Dx
Point-Slope Form
y=m(x-X1)+y1
Used: When a slope and a point are given
Slope-Intercept Form
y=mx+b
Used: Almost always whenever an “equation” of a line is asked for
General Form
Ax+By+C=0
Must have: A-B-C order, no fractions, Ax_>0
Used: Sparingly => only when asked
Vertical line
X=c,
where c is the x-coordinate of the points
Used: When slope is undefined
Horizontal line
Y=b,
where b is the y-coordinate
Used: When the slope is 0
Perpendicular lines
Slopes are negative reciprocals
m1=1/m2 flip and change sign
Parallel lines
m1=m2
Slopes are the same