GSoC 2020 - Week 9

Key highlights of this week’s work are:

• Fixed periodicity of trigonometric function

  • This was a long pending issue. The _peeloff_pi method of sin had to be rectified to reduce the symbolic multiples of pi in trigonometric functions. As a result of this fix, now sin(2*n*pi + 4) automatically evaluates to sin(4), when n is an integer.
    
    

• Fixed limit evaluations related to trigonometric functions

  • In this PR, we added _eval_nseries method to both sin and cos to make the limit evaluations more robust when it comes to trigonometric functions. We also added a piece of code to cos.eval method so that the limit of cos(m*x), where m is non-zero, and x tends to oo evaluates to AccumBounds(-1, 1).