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Find i) sin 15 ii) cos 15 using the relation

sin(A-B)= sinAcosB-cosAsinB

cos(A-B)=cosAcosB+sinAsinB

1
by anudeepd2

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sin(A-B)= sinAcosB-cosAsinB

cos(A-B)=cosAcosB+sinAsinB

by anudeepd2

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= sin(45-30)

= sin 45 cos 30 - cos 45 sin 30

= 1/√2 × √3/2 - 1/√2 × 1/2

= √3/2√2 - 1/2√2

= (√3-1)/2√2

cos(15)

= cos(45-30)

= cos 45 cos 30 + sin 45 sin 30

= 1/√2 × √3/2 + 1/√2 × 1/2

= √3/2√2 + 1/2√2

= (√3+1)/2√2