Exact equations and integrating factors (K-A)

• Exact equations intuition 1 (proofy) (K-A)
• Exact equations intuition 2 (proofy) (K-A)
• Exact equations example 2 (K-A)
• Exact equations example 3 (K-A)
• Integrating factors 1 (K-A)
• Integrating factors 2 (K-A)