Найти среднее значение y=x^3-ln x +cos x — z z=cos x при x>=1 z=abs(x) при x<1 - QBasic(Бейсик)

INPUT "vvedite nachalo intervala ", x1
INPUT "vvedite konec intervala ", x2
FOR x = x1 TO x2
    IF x >= 1 THEN z = COS(x) ELSE z = ABS(x)
    y = x ^ 3 - LOG(x) + COS(x) - z
    sum = sum + y
NEXT
sred = sum / (x2 - x1 + 1)
PRINT "srednee="; sred