Question

cos 15º - sin 15°
cos 15° + sin 15°
1
53​

Answer 1

hey shubham it is only format not the solution of ur question

sin (A - B) = Sin A Cos B - Cos A sin B

Let A = 45° and B = 30°

sin (45° - 30°) = Sin 45° Cos 30° - Cos 45° sin 30°

sin (45° - 30°) = (1/√2)(√3/2) - (1/√2)(1/2)

sin 15° = (√3 - 1) / (2√2)

cos (A - B) = Cos A Cos B + Sin A sin B

Let A = 45° and B = 30°

cos (45° - 30°) = Cos 45° Cos 30° + Sin 45° sin 30°

cos (45° - 30°) = (1/√2)(√3/2) + (1/√2)(1/2)

cos 15° = (√3 + 1) / (2√2)