Precalculus Examples

$\cos (12) \cos (13) - \sin (12) \sin (13)$

Step 1

Evaluate $\cos (12)$ .

$0.9781476 \cos (13) - \sin (12) \sin (13)$

Step 2

Evaluate $\cos (13)$ .

$0.9781476 \cdot 0.97437006 - \sin (12) \sin (13)$

Step 3

Multiply $0.9781476$ by $0.97437006$ .

$0.95307774 - \sin (12) \sin (13)$

Step 4

Evaluate $\sin (12)$ .

$0.95307774 - 1 \cdot 0.20791169 \sin (13)$

Step 5

Multiply $- 1$ by $0.20791169$ .

$0.95307774 - 0.20791169 \sin (13)$

Step 6

Evaluate $\sin (13)$ .

$0.95307774 - 0.20791169 \cdot 0.22495105$

Step 7

Multiply $- 0.20791169$ by $0.22495105$ .

$0.95307774 - 0.04676995$

Step 8

Subtract $0.04676995$ from $0.95307774$ .

$0.90630778$