Exact values of cosine
Exact values of cosine.
- Learn the exact values for 0°, 30°, 45°, 60° and 90° where defined.
- Use the special right triangles to rebuild the table.
- A root or fraction is exact; a rounded decimal is not.
Example 1
Find the exact value without a calculator.
| 0° | 30° | 45° | 60° | 90° | |
|---|---|---|---|---|---|
| cosine |
Use the special triangles 30°–60°–90° and 45°–45°–90°. Keep roots and fractions exact.
Example 2
Find the exact value without a calculator.
| 0° | 30° | 45° | 60° | 90° | |
|---|---|---|---|---|---|
| cosine |
Use the special triangles 30°–60°–90° and 45°–45°–90°. Keep roots and fractions exact.
Your turn
Find the exact value without a calculator.
Check answer
| 0° | 30° | 45° | 60° | 90° | |
|---|---|---|---|---|---|
| cosine |
Use the special triangles 30°–60°–90° and 45°–45°–90°. Keep roots and fractions exact.
Find the exact value without a calculator.
Check answer
| 0° | 30° | 45° | 60° | 90° | |
|---|---|---|---|---|---|
| cosine |
Use the special triangles 30°–60°–90° and 45°–45°–90°. Keep roots and fractions exact.
Find the exact value without a calculator.
Check answer
| 0° | 30° | 45° | 60° | 90° | |
|---|---|---|---|---|---|
| cosine |
Use the special triangles 30°–60°–90° and 45°–45°–90°. Keep roots and fractions exact.
Find the exact value without a calculator.
Check answer
| 0° | 30° | 45° | 60° | 90° | |
|---|---|---|---|---|---|
| cosine |
Use the special triangles 30°–60°–90° and 45°–45°–90°. Keep roots and fractions exact.
Find the exact value without a calculator.
Check answer
| 0° | 30° | 45° | 60° | 90° | |
|---|---|---|---|---|---|
| cosine |
Use the special triangles 30°–60°–90° and 45°–45°–90°. Keep roots and fractions exact.
Find the exact value without a calculator.
| 0° | 30° | 45° | 60° | 90° | |
|---|---|---|---|---|---|
| cosine |
Use the special triangles 30°–60°–90° and 45°–45°–90°. Keep roots and fractions exact.
Find the exact value without a calculator.
| 0° | 30° | 45° | 60° | 90° | |
|---|---|---|---|---|---|
| cosine |
Use the special triangles 30°–60°–90° and 45°–45°–90°. Keep roots and fractions exact.
Find the exact value without a calculator.
| 0° | 30° | 45° | 60° | 90° | |
|---|---|---|---|---|---|
| cosine |
Use the special triangles 30°–60°–90° and 45°–45°–90°. Keep roots and fractions exact.
Find the exact value without a calculator.
| 0° | 30° | 45° | 60° | 90° | |
|---|---|---|---|---|---|
| cosine |
Use the special triangles 30°–60°–90° and 45°–45°–90°. Keep roots and fractions exact.
Find the exact value without a calculator.
| 0° | 30° | 45° | 60° | 90° | |
|---|---|---|---|---|---|
| cosine |
Use the special triangles 30°–60°–90° and 45°–45°–90°. Keep roots and fractions exact.