

The ( x, y ) ( x, y ) coordinates of this point can be described as functions of the angle. Let ( x, y ) ( x, y ) be the endpoint on the unit circle of an arc of arc length s. In a unit circle, the length of the intercepted arc is equal to the radian measure of the central angle t. Ī unit circle has a center at ( 0, 0 ) ( 0, 0 ) and radius 1 1. This means x = cos t x = cos t and y = sin t. The coordinates x x and y y will be the outputs of the trigonometric functions f ( t ) = cos t f ( t ) = cos t and f ( t ) = sin t, f ( t ) = sin t, respectively.

The four quadrants are labeled I, II, III, and IV.įor any angle t, t, we can label the intersection of the terminal side and the unit circle as by its coordinates, ( x, y ).

We label these quadrants to mimic the direction a positive angle would sweep. Recall that the x- and y-axes divide the coordinate plane into four quarters called quadrants. Using the formula s = r t, s = r t, and knowing that r = 1, r = 1, we see that for a unit circle, s = t. The angle (in radians) that t t intercepts forms an arc of length s. To define our trigonometric functions, we begin by drawing a unit circle, a circle centered at the origin with radius 1, as shown in Figure 2. Finding Function Values for the Sine and Cosine Then we can discuss circular motion in terms of the coordinate pairs. To do so, we need to define the type of circle first, and then place that circle on a coordinate system. In this section, we will examine this type of revolving motion around a circle. Described as an observation wheel, riders enjoy spectacular views of the Burj Khalifa (the world's tallest building) and the Palm Jumeirah (a human-made archipelago home to over 10,000 people and 20 resorts) as they travel from the ground to the peak and down again in a repeating pattern. Located in Dubai, the most populous city and the financial and tourism hub of the United Arab Emirates, the wheel soars to 820 feet, about 1.5 tenths of a mile. Looking for a thrill? Then consider a ride on the Ain Dubai, the world's tallest Ferris wheel. Figure 1 The Singapore Flyer was the world’s tallest Ferris wheel, until being overtaken by the High Roller in Las Vegas and the Ain Dubai in Dubai.
