[BUG] 处理多项式时的若干问题
>> :mode polyn
Switch into polynomial mode.
>> (1.2x)^(1+2)
in> (1.2x)^(1+2)
out> 1.2x^3|1
------------------------
目前改进
>> :mode polyn
Switch into polynomial mode.
>> 1.2x^1.2-x^1
in> 1.2x^1.2-x^1
out> +1.2x^1.2-1x
------------------------
>> 1.2x^1.2-x^1.2
in> 1.2x^1.2-x^1.2
out> +0.2x^1.2
------------------------