Trigonometry Examples

$\cos (\frac{π}{36}) \cdot \cos (\frac{35 π}{36}) - \sin (\frac{35 π}{36}) \cdot \sin (\frac{π}{36})$

Step 1

Simplify each term.

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Step 1.1

Evaluate $\cos (\frac{π}{36})$ .

$0.99619469 \cdot \cos (\frac{35 π}{36}) - \sin (\frac{35 π}{36}) \cdot \sin (\frac{π}{36})$

Step 1.2

Evaluate $\cos (\frac{35 π}{36})$ .

$0.99619469 \cdot - 0.99619469 - \sin (\frac{35 π}{36}) \cdot \sin (\frac{π}{36})$

Step 1.3

Multiply $0.99619469$ by $- 0.99619469$ .

$- 0.99240387 - \sin (\frac{35 π}{36}) \cdot \sin (\frac{π}{36})$

Step 1.4

Evaluate $\sin (\frac{35 π}{36})$ .

$- 0.99240387 - 1 \cdot 0.08715574 \cdot \sin (\frac{π}{36})$

Step 1.5

Multiply $- 1$ by $0.08715574$ .

$- 0.99240387 - 0.08715574 \cdot \sin (\frac{π}{36})$

Step 1.6

Evaluate $\sin (\frac{π}{36})$ .

$- 0.99240387 - 0.08715574 \cdot 0.08715574$

Step 1.7

Multiply $- 0.08715574$ by $0.08715574$ .

$- 0.99240387 - 0.00759612$

Step 2

Subtract $0.00759612$ from $- 0.99240387$ .

$- 1$