Question

Given that sin(A+B)=sinAcosA+cosAsinB,find the value of sin75°

Answer 1

Solution :

Sin75

= sin(45+30)

= sin45cos30+cos45sin30

[sin(A+B)=sinAcosA+cosAsinB]

= (1/√2)(√3/2)+(1/√2)(1/2)

= (√3/2√2)+1/(2√2)

= (√3+1)/2√2

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