Modeling with Trigonometric Functions and Circle Characteristics Unit 8
Trig. Stuff
Special Right Triangles
This is half of an equilateral triangle The hypotenuse = short leg times 2 The long leg = short leg times √3
This comes from half of a square The legs are equal Hypotenuse = leg times √2 Leg = ½ the hypotenuse times √2
The Unit Circle
Convert from degrees to radian
Convert from radian to degrees
How do I find the amplitude of a trig. Function? The amplitude equals the absolute value of a. a is located in front of the trig. function Example: f(x) = -3cos(x- π ) + 4 What is the amplitude? 3
How do I find the period of a trig. Function?
Trig. Identities
Stuff about circles!
Theorem Radius to a tangent: Right angle If a radius is drawn to a tangent, then the radius is perpendicular to the tangent.
Theorem Congruent chords are equidistant from the center of the circle.
Theorem If a radius is perpendicular to a chord, then it bisects the chord and its arcs.
“Hat Theorem” If two tangents are drawn to a circle from an exterior point, then the tangent segments are congruent.
Equation of a circle
Distance Formula
Midpoint Formula
Length of an arc =
Area of a sector=
Central Angle = Same as the arc
Inscribed Angle = ½ the arc
Angle inside the circle formed by two chords = ½ the sum of the arcs
Angle outside the circle = ½ the difference of the arcs
What do you know about a quadrilateral inscribed in a circle? It’s opposite angles are supplementary (they have a sum of 180º).
Area of an equilateral triangle