Most of us took mathematics courses from mathematicians—Bad Idea!
Mathematicians see mathematics as an area of study in its own right.
The rest of us use mathematics as a precise language for expressing relationships
among quantities in the real world, and as a tool for deriving
quantitative conclusions from these relationships. For that purpose, mathematics
courses, as they are taught today, are seldom helpful and are often
downright destructive.
As a student, I promised myself that if I ever became a teacher, I would
never put a student through that kind of teaching. I have spent my life
trying to find direct and transparent ways of seeing reality and trying to
express these insights quantitatively, and I have never knowingly broken
my promise.
With rare exceptions, the mathematics that I have found most useful was
learned in science and engineering classes, on my own, or from this book.
Street-Fighting Mathematics is a breath of fresh air. Sanjoy Mahajan teaches
us, in the most friendly way, tools that work in the real world. Just when
we think that a topic is obvious, he brings us up to another level. My
personal favorite is the approach to the Navier–Stokes equations: so nasty
that I would never even attempt a solution. But he leads us through one,
gleaning gems of insight along the way.
In this little book are insights for every one of us. I have personally
adopted several of the techniques that you will find here. I recommend
it highly to every one of you