Question

напишите программу КуБейсик. Вычислить $\int\limits^a_b {f(x)} \, dx$ с точностью Е=0,001 а=0 b=1 значение=0,5   .Методом левых прямоугольников
$x^{3} e^{ x^{2} }$

Answer 1

DECLARE FUNCTION f# (x AS DOUBLE)
DECLARE FUNCTION Integ# (a AS DOUBLE, b AS DOUBLE, n AS LONG)

'Main program
DIM eps AS DOUBLE, n AS LONG, s AS DOUBLE, s1 AS DOUBLE
DIM a AS DOUBLE, b AS DOUBLE
CLS
a = 0: b = 1: eps = .001
n = 100
s = Integ#(a, b, 10#)
DO
   s1 = s
   s = Integ#(a, b, n)
   n = n * 2
LOOP UNTIL ABS(s - s1) <= eps
PRINT s
END

FUNCTION f# (x AS DOUBLE)
   f# = x ^ 3 * EXP(x ^ 2)
END FUNCTION

FUNCTION Integ# (a AS DOUBLE, b AS DOUBLE, n AS LONG)
   DIM h AS DOUBLE, xb AS DOUBLE, x AS DOUBLE
   DIM s AS DOUBLE, i AS INTEGER
   h = (b - a) / n
   s = 0
   xb = a
   FOR i = 0 TO n - 1
      x = xb + i * h
      s = s + f(x) * h
   NEXT i
   Integ# = s
END FUNCTION

Результат выполнения программы:
 .4991509793572241
Погрешность не превышает 0.001 при контрольном значении, равном 0.5