Rusczyk R. The Art of Problem Solving. Vol 2. Sol. Man. 7ed 2017

Textbook in PDF format

A classic problem solving textbook for students in grades 9-12 who are preparing for advanced high school contests like the AMC 12, AIME, and the Harvard-MIT Mathematics Tournament.
Prove it!
Logarithms
Not just for right triangles
More triangles!
Cyclic quadrilaterals
Conics and polar coordinates
Polynomials
Functions
Taking it to the limit
Complex numbers
Vectors and matrices
Cross products and determinants
Analytic geometry
Equations and expressions
Inequalities
Combinatorics
Sequences and series
Counting in the twilight zone
Again and again
Probability
Find it and make it
Collinearity and concurrency
Geometry tidbits
Number theory
Diophantine equations
Graph theory
Parting shots