Pre-Calc Unit 1
19 flashcards · Mathematics · by Logan Pollack
A function is increasing when...
it is going up
a function is decreasing when...
it is going down
a function is constant when...
it is horizontal
The slope of a non-vertical line passing through two points, (x1,y1)(x_1,y_1)(x1,y1) and (x2,y2)(x_2, y_2)(x2,y2) is given by
y2−y1x2−x1=m\frac{y_2-y_1}{x_2-x_1} = mx2−x1y2−y1=m
slope-intercept form
y=mx+by=mx+by=mx+b
point-slope form
y−y1=m(x−x1)y-y_1 = m(x-x_1)y−y1=m(x−x1)
horizontal line equation
y=ky=ky=k
vertical line equation
x=hx=hx=h (not a function)
Parallel Lines Slope
Slopes of parallel lines are the same
Perpendicular Lines Slope
Slopes are opposite reciprocals
The equation of a circle with a center (h,k) and radius r is
(x−h)2+(y−k)2=r2(x-h)^2 + (y-k)^2 = r^2(x−h)2+(y−k)2=r2
Any point that lies on the graph of a function is called a solution point since its coordinates will be a solution of the equation of the function
x-intercepts
the points where a graph crosses the x-axis. Substitute 0 for y, solve for x. X-intercepts are written as an ordered pair
y-intercepts
The point where a graph crosses the y-axis. Substitute 0 for x, solve for y. Y-intercepts are written as an ordered pair. If there are multiple y-intercepts the graph is not a function
Algebraic Tests for Symmetry x-axis if replacing:
y with -y yields an equivalent equation when solved for y
Algebraic Tests for Symmetry y-axis if replacing:
x with -x yields an equivalent equation when solved for y
Algebraic Tests for Symmetry y=xy=xy=x if replacing:
x with y and y with x yields and equivalent equation
Algebraic Tests for Symmetry Origin if replacing
x with -x and y with -y yields an equivalent equation when solved for y
Symmetry
The most common type of symmetry in graphs are line symmetry, and it may be with respect to the x or y axes, or the line y=xy=xy=x . Another common type of symmetry is point symmetry with respect to the origin When you fold the Cartesian plane with respect to a line (such as the x-axis), a graph contains line symmetry (with respect to that line) if the two portions of the graph coincide.