Question

if A is an acute angle and sinA\2 =3\5, find the value of sinA.

Answer 1

Answer:

$\sin(a \div 2) = 3 \div 5 \\ hence \: \\ a \div 2 = 37 \\ now \: \\ \sin(a) = 2 \sin(a \div 2) \cos(a \div 2) \\ also \\ \cos(a \div 2) = 4 \div 5 \\ hence \: \\ \: \sin(a) = 2 \times( 4 \div 5) \times( 3 \div 5) \\ = 24 \div 25 \\ hence \: \\ \sin(a) = 24 \div 25$