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Concept of variables, If -Then , If - Then – Else, Go To, Do - Loop; Lab2 (VBA1): Sub Lab2_Pr1() Dim k As Integer, n%, x As Double, y# Dim a As String, b$ k = Cells(2, 2): n = Cells(2, 3) Cells(4, 2) = k: Cells(4, 3) = n: Cells(4, 4) = k + n x = Cells(2, 2): y = Cells(2, 3) Cells(5, 2) = x: Cells(5, 3) = y: Cells(5, 4) = x + y a = Cells(2, 2): b = Cells(2, 3) Cells(6, 2) = a: Cells(6, 3) = b: Cells(6, 4) = a + b End Sub 1. Write on an Excel worksheet the values and strings below, then insert a modul-sheet, type in the given program (Lab2_Pr1), save the file, and run the program. 2. Write a VBA program to the given 3. Write a VBA program using the given flowsheet, then run the program using flowsheet to approximate by halving Debug Step Into F8 method the root of the equation x^4 – 81 = 0. Give the starting value of the variables a and b by InputBox. The Start table written by the program should be the following: write: „x” „x cube” x=2 write: x, x=x+1 yes x<=5 ? x3 a 1 1 2,75 2,75 2,75 2,96875 2,96875 2,96875 2,996094 2,996094 2,996094 b 8 4,5 4,5 3,625 3,1875 3,1875 3,078125 3,023438 3,023438 3,009766 3,00293 m 4,5 2,75 3,625 3,1875 2,96875 3,078125 3,023438 2,996094 3,009766 3,00293 2,999512 f(m) 329,06 -23,81 91,68 22,23 -3,32 8,77 2,56 -0,42 1,06 0,32 -0,05 Start give: a, b fa=a^4-81: fb=b^4-81 m=(a+b)/2 : fm=m^4-81 write: a, b, m, fm no yes fa*fm<0 ? a=m : fa=fm b=m : fb=fm no Stop Write the 3. program using Do-Loop statement, too! yes Abs(fm)>0,1 ? no Stop Lab3 (VBA2): For - Next (Sequences) ; Function (Area approximation) 1. Write a program where the input is an m0 integer, and the program calculates the reciprocals of the first (m+1) odd numbers, then evaluates the following sum: m 1 1 1 1 S 1 ..... 3 5 7 2m 1 Use the For k=0 To m … Next k statement. The output of the program is shown in the table (right, m=10). 2. Write a program for the approximation of the area between the x axis and the graph of the function f(x) on the intervall [a;b], as it is shown on the figure. To evaluate the area divide the intervall [a;b] into n equidistant parts, and approximate the area under the curve by the sum of the trapezoids’ area, where the height of the trapezoids is h=(b-a)/n. (On the figure the number of trapezoids is n=3.) The elements of the sequence are now the trapezoids: t1 h y f(x) x a a+h f a f a h f a h f a 2h f a (n 1) * h f b ; t2 h ; ... ; t n h 2 2 2 For the definition of the function f(x) use in the program a VBA Function as it is shown in the example below: For the input of the boundaries of the intervall Function f(x#) As Double f = 4 / (1 + x ^ 2) End Function (a, b) and of the number of trapezoids (n) use Inputbox . The outputs of the program (if a=0, b=1, n=10) are shown in the table (right). a+2h b