SageMath
SageMath is a free open-source mathematics software system licensed under the GPL. It builds on top of many existing open-source packages: NumPy, SciPy, matplotlib, Sympy, Maxima, GAP, FLINT, R and many more. Access their combined power through a common, Python-based language or directly via interfaces or wrappers. Offifial documents
Symbolic Computation
Symbolic Equations and Inequalities
Questions - ASKSAGE: Sage Q&A Forum
Online environment
Examples
Ocean Science Hack: Sageで方程式を解く
Ocean Science Hack: Sageで方程式
Ocean Science Hack: Sageで数学 素数
級数
code:python
sum(1/x^2,x,1,oo)
1/6*pi^2
A First Course in Linear Algebra (A Free Textbook)
fourier series - using sage - YouTube
preCalculus 1200 Intro to SAGE! - YouTube
Algorithmic Graph Theory and Sage
Tips
simplify
exponentialize
substitute
convert function to variable - ASKSAGE: Sage Q&A Forum
Defining constants after solving ODE/PDE - ASKSAGE: Sage Q&A Forum
substitute expression instead of formal function symbol - ASKSAGE: Sage Q&A Forum
Use a symbolic solved variable in another later equation - ASKSAGE: Sage Q&A Forum
What does assume(x, "real")? - ASKSAGE: Sage Q&A Forum
Un peu de math...: How to handle float error for plots near discontinuities in Sage
Substitute variable in differential equation - ASKSAGE: Sage Q&A Forum
Tutorials
Sage for undergraduates (2014)
Sage by Hiroshi TAKEMOTO
Introduction to Sage - YouTube
Dr. Michael O'Sullivan
Links
ウィキペディア SageMath