Question

Show that sin A = $\frac{sin 3A}{(1 + 2 cos 2A)}$. Hence find the value of sin 15°.

Answer 1

Answer:

sin15⁰ = = 1/(√2(1+√3))

Step-by-step explanation:

sin3A/(1+2cos2A)

= (3sinA - 4 sin³A)/(1+2(1-2sin²A))

= sinA(3 - 4sin²A)/(3 - 4sin²A)

= sinA

Hence

sinA = sin3A/(1+2cos2A)

put A=15⁰

sin15⁰ = sin45⁰/(1+2cos30⁰)

= (1/√2)/(1+2(√3/2))

= (1/√2)/(1+√3)

= 1/(√2(1+√3))

I hope this answer helps you

Answer 2

Step-by-step explanation:

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