as shown in attached chart I have two variables ( X, YC) to get Y value.
the equation for each curve are
- y = 0.0331x2 - 0.0783x + 0.0606
y = 0.0321x2 - 0.0751x + 0.0558
y = 0.033x2 - 0.0784x + 0.0571
y = 0.0337x2 - 0.0808x + 0.0578
how can I get a function f(y)=(X, YC) from this chart ?