Lesson Summary for April 17th, Trigonometry: Special Angles
The special angles are 0º, 30º, 45º, 60º and 90º which answers when using sine, cosine and tangent, can be found and recalled through a method below.
How to recall
1. Start by writing down the angles 0º, 30º, 45º, 60º, 90º
2. Label the numbers like shown in the picture below from 0 to 4 respectively.
3. Square root all the numbers.
4. Divide all the numbers by 2 to get the answer for sine for each of the special angles.
5. Then inverse the order of the answers for the sine(special angle) to get the answer for the cosine(special angle).
6. Afterwards, divide the answers gotten for sine(special angle) by the answers gotten for cosine to get the answers for tan(special angle).