Unit circle
It’s a fairly fundamental tool for solving trigonometric problems.
trigonometric problems
Reference Angle
The notion reference angle would be the very FIRST thing to understand before solving any trig equations.
reference angle
First thing first, it’s always the angel with X-axis and Terminal Ray.
X-axis
Terminal Ray
Absolute value graphs
Refer to Khan academy: Absolute value graphs
Permutations & Combinations
Aside from probability, Permutations and Combinations are essential tools for statistics.
Permutations
Combinations
Ellipse
Ellipse is twisted circle, it got major features and equation from circle.
Ellipse got TWO radiuses (or radii):
Major radius
Minor radius
Signs
Before solving a trig equation, need look at the sign of the equation, AND identify which one or multiple quadrants will the solutions land in.
sign
quadrants
Quadrant I
Quadrant II
sin(x)