Trigonometric functions

Definition

Trigonometric functions are mathematical functions that relate the angles of a triangle to the lengths of its sides. They are fundamental in studying periodic phenomena, wave patterns, and oscillatory motions. Key trigonometric functions include sine, cosine, and tangent, which can also be defined using the unit circle, making them vital for understanding limits and continuity in calculus.

5 Must Know Facts For Your Next Test

1. The sine function is defined as the ratio of the length of the opposite side to the hypotenuse in a right triangle.
2. The cosine function is defined as the ratio of the length of the adjacent side to the hypotenuse in a right triangle.
3. The tangent function is the ratio of sine to cosine, or equivalently, the ratio of the opposite side to the adjacent side.
4. Trigonometric functions are periodic with a period of 2π for sine and cosine, while tangent has a period of π.
5. Understanding limits involving trigonometric functions is key to solving problems related to their continuity, especially as angles approach certain critical points like 0 or π/2.

Review Questions

• How do trigonometric functions illustrate the concept of limits when approaching specific angles?
  • Trigonometric functions exhibit interesting behaviors as they approach specific angles, particularly at points like 0 and π/2. For example, as the angle approaches 0, both sine and tangent approach 0 while cosine approaches 1. Understanding these limits helps clarify how these functions behave near critical points, which is essential in determining their continuity and differentiability.
• In what ways do the properties of trigonometric functions contribute to their continuity on the unit circle?
  • Trigonometric functions are continuous on the unit circle because they can be expressed using circular motion. The sine and cosine functions take on every value between -1 and 1 smoothly as angles vary from 0 to 2π. This continuous nature ensures that there are no breaks or jumps in their graphs, allowing for seamless transition as we move around the unit circle.
• Evaluate how understanding limits and continuity enhances your ability to solve problems involving trigonometric functions.
  • Grasping limits and continuity greatly aids in solving problems involving trigonometric functions by providing insights into their behaviors at critical angles and intervals. For instance, knowing how sine and cosine behave near 0 enables us to apply L'Hôpital's rule effectively when calculating derivatives or integrals involving these functions. Additionally, recognizing points of discontinuity helps avoid pitfalls when analyzing complex trigonometric expressions or solving equations.

Related terms

Unit Circle: A circle with a radius of one centered at the origin of a coordinate plane, used to define trigonometric functions for all angles.

Limits: The value that a function approaches as the input approaches a certain value, which is crucial for understanding the behavior of trigonometric functions.

Continuity:

A property of functions where they are unbroken or uninterrupted over a given interval, essential for the smooth behavior of trigonometric functions.