Question

Find cos15 if cos(a-b)=cosa cosb + sina sinb taking suitable a and b

Answer 1

Heya user !!!

Here's the answer you are looking for

if cos(a-b)=cosa cosb + sina sinb and we have to find cos15

15 can be expressed as (45 - 30)

So,

cos 15 = cos (45 - 30)

= cos45cos30 + sin45sin30

= (1/√2)(√3/2) + (1/√2)(1/2)

= √3/2√2 + 1/2√2

= (√3 + 1) / 2√2


★★ HOPE THAT HELPS ☺️ ★★

Answer 2

Heya, find the answer in the attached image.

Hope this helps. . . . . if it really helped, then please mark it as the BRAINLIEST and please say a thanks.

Thanks.