@command_block 额您好像把$2n$写错地方了……应该加在最后面那个括号里

$(0,y_0*y'_0)...(2n,y_n*y'_n)...(n,y_{2n}*y'_{2n})$

应该是

$(0,y_0*y'_0)...(n,y_n*y'_n)...(2n,y_{2n}*y'_{2n})$