Question

if A+B=45° the value of cosA•cosB-sinA•sinB​

Answer 1

Answer:

1/√2

Step-by-step explanation:

cos A. cos B - sin A. sin B

= cos ( A + B)

= cos 45°

= 1/√2

Therefore the value of cos A. cos B - sin A. sin B is 1/√2