Question

If sin A =
3
find value of sin 3A.​

Answer 1

Step-by-step explanation:

sinA=3/5

√(1-cos²A)=3/5

1-cos²A=9/25

cos²A=1- 9/25

cos²A= 16/25

cosA=4/5

hence cosA=4/5 and sinA=3/5

sin3A

sin(2A+A)

sin2A•cosA+cos2A•sinA

2sinAcosA•cosA+(cos²A-sin²A)sinA

(2•3/5•4/5•4/5)+{(4/5)²-(3/5)²}3/5

(96/125)+{16/25-9/25}3/5

(96/125)+(7/25)3/5

(96/125)+(21/125)

(96+21)/125

117/125

#666