Question

sin 15 degrees + cos 15 degrees equal to with explanation please please​

Answer 1

Answer:

Now cos15o−sin15o

=2(21cos15o−21sin15o)

=2(sin45ocos15o−cos45osin15o)

=2sin(45o−15o)=2sin30o=2×21=21

Answer 2

given:- cos15+sin15=? we needs to answer

solution:- cos15=cos(45-30)

hence, using

cos(A-B)=cosA cosB+ sinA Sinn

therefore, we get

cos15= cos(45-30) =cos45 cos30+sin45 sin30

cos 15=root2/4 (root3+1) ....(1)

similarly ,

sin 15 = sin(45-30)= root2/4(root3-1) .....(2)

(using sin(A-B)=sinAcosB-cosAsinB)

From (1) and (2) we get

sin 15 + cos 15 = root2/4(root3+1+root3-1)

=root2/4(2root3)

=root2/2 (root3)