Question

When you enter cos(30°) into your calculator, you get the answer of 0.5 and when you enter into your calculator cos(-30°) you still get 0.5. Explain to the best of your ability why you think you get the same answer even though the angle you enters is different?​

Answer 1

The reason why you get the same answer when you enter cos(30°) and cos(-30°) into your calculator is because cosine is a periodic function, which means that the same value is repeated after a certain interval. In the case of cosine, the interval is always 360°, so cos(30°) and cos(-30°) are equivalent because they are both equal to 30° away from 0°. Therefore, they both have the same value, which is 0.5.