Question

cos(π÷4+a)cos(π÷4−b)+sin(π÷4+a)sin(π÷4−b)​

Answer 1

Answer:

Step-by-step explanation:

Step-by-step explanation:

cos 45 cos A-sin 45 sin A.cos45 Cos B+ sin 45 sin B-(sin 45 cos A +cos 45 sinA).(sin 45 cos A-cos 45 sin A)

1/√2(Cos A-sin A)1/√2(cos B - sin B)-1/√2(cos A + sin A)1/√2(cos A - sin A)