Answer:
Use Trigonometric formulae to simplify expressions
Explanation:
Re-order to group the x and y,
Sin(y) / Sin(a+y) = x
to differentiate apply d/dx to both sides
Sin(y) / Sin(a+y) =
x
use division rule on left side which will give
Cos(y)Sin(a+y) -
Cos(a+y)Sin(y) / Sin²(a+y) = 1
Group them so dy/dx is on the left hand side:
= Sin²(a+y) / Cos(y)Sin(a+y) - Cos(a+y)Sin(y)
Apply trigonometric sum formula to expand Sin(a+y) and Cos(a+y),
= Sin²(a+y) / Cos(y)[Sin(a)Cos(y) + Cos(a)Sin(y)] - Sin(y)[Cos(a)Cos(y) - Sin(a)Sin(y)]
Simplify it
= Sin²(a+y) / (Cos²(y) + Sin²(y))(Sin(a))
= Sin²(a+y) / (1)(Sin(a))