The cosine function, represented as \( \cos \), is another principal trigonometric function linked to the x-coordinate on the unit circle. The cosine of an angle\( \theta \) defines the length of the horizontal leg (adjacent side) of a right triangle. Similar to sine, it's essential to choose the correct mode on the calculator based on radians or degrees. Here's how it's generally calculated:
- For 0.15 radians (often inferred as radians due to decimal format), \( \cos(0.15) \approx 0.9888 \).
- Switching to degree mode for 283 degrees, the approximation becomes \( \cos(283^\circ) \approx 0.4695 \).
Cosine, like sine, can be negative or positive based on the quadrant of the angle, reflecting its symmetrical properties about the unit circle's center.