From a978febdd78ca197ca9572dfcb86e1cf7249fdc6 Mon Sep 17 00:00:00 2001
From: Andrew Lorimer <andrew@lorimer.id.au>
Date: Thu, 16 May 2019 16:27:51 +1000
Subject: [PATCH 1/1] [spec] DEs of the dependent variable

---
 spec/calculus.md | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/spec/calculus.md b/spec/calculus.md
index c6818d4..30a2957 100644
--- a/spec/calculus.md
+++ b/spec/calculus.md
@@ -396,3 +396,7 @@ e.g. ${\left(dy^2 \over d^2 x\right)}^3$: order 2, degree 3
 ### Verifying solutions
 
 Start with $y=\dots$, and differentiate. Substitute into original equation.
+
+### Function of the dependent variable
+
+If ${dy \over dx}=g(y)$, then ${dx \over dy} = 1 \div {dy \over dx} = {1 \over g(y)}$. Integrate both sides to solve equation. Only add $c$ on one side. Express $e^c$ as $A$.
-- 
2.43.2