# How are trigonometric functions related to circles?

## How are trigonometric functions related to circles?

An arc of the unit circle has the same length as the measure of the central angle that intercepts that arc. Also, because the radius of the unit circle is one, the trigonometric functions sine and cosine have special relevance for the unit circle.

## What are the 6 trig functions unit circle?

These six functions and their abbreviations are sine (sin), cosine (cos), tangent (tan), secant (sec), cosecant (csc), and cotangent (cot).

What does O stand for in trigonometry?

circle
Circle-related Symbols

Symbol Name Explanation Example
O Variable for circle (or center of circle) If circles and share the same radius, then they are congruent.
⊙ P Circle centered around point If P ≠ Q , then ⊙ P ≠ ⊙ Q .
r Radius of circle r = A π
d Diameter of circle d = 2 r

### Is trig about circles or triangles?

Trigonometry can be used to find the side lengths of right triangles. Use the interactive below to see how a right triangle with a hypotenuse of fixed length extends to a circular model. Later in this section you will see how to utilize right triangle trigonometry to find coordinates on circles centered at the origin.

### What is sin Cos Tan unit circle?

The sine of the angle is the coordinate of the point where the terminal side of the angle intersects the unit circle, the cosine of the angle is the coordinate of this same point, and the tangent of the angle is the slope of the line passing through the same point and the origin.

What is the fastest way to learn the unit circle?

To memorize the unit circle, use the acronym ASAP, which stands for “All, Subtract, Add, Prime.” Each word represents a different quadrant in the unit circle. “All” corresponds with the top right quadrant in the circle, or the first quadrant.

## What does O stand for in Sohcahtoa?

Acronym. Definition. SOHCAHTOA. Sine (Opposite over Hypotenuse), Cosine (Adjacent over Hypotenuse), Tangent (Opposite over Adjacent)

## What is the equation for a circle?

We know that the general equation for a circle is ( x – h )^2 + ( y – k )^2 = r^2, where ( h, k ) is the center and r is the radius.

How do you write the function of a circle?

The general equation of a circle is (x – h)2 + (y – k)2 = r2, where (h, k) represents the location of the circle’s center, and r represents the length of its radius. Circle A first has the equation of (x – 4)2 + (y + 3)2 = 29.

### How is sine related to circle?

Using the unit circle, the sine of an angle t equals the y-value of the endpoint on the unit circle of an arc of length t whereas the cosine of an angle t equals the x-value of the endpoint.

### Where is Cos on the unit circle?

For a given angle measure θ , draw a unit circle on the coordinate plane and draw the angle centered at the origin, with one side as the positive x -axis. The x -coordinate of the point where the other side of the angle intersects the circle is cos(θ) , and the y -coordinate is sin(θ) .