3月底,农业总产值=a(1-x%)^2
工业总产值=2a(1+x%)^2
所以多2a(1+x%)^2-a(1-x%)^2
=2a(1+x/50+x^2/10000)-a(1-x/50+x^2/10000)
=a+3ax/50+ax^2/10000亿元