The document discusses different types of optimization techniques including nonlinear optimization, unconstrained optimization, and equality constrained optimization. Nonlinear optimization involves using Taylor series expansions to minimize the residue between a data fit curve and actual data points. Unconstrained optimization seeks to minimize a function subject to variables being greater than or equal to 0. Equality constrained optimization uses Lagrange equations to minimize a function subject to an equality constraint, where the Lagrange multiplier determines if the solution is a minimum or maximum.