數(shù)值計算方法大作業(yè)

1、目錄第一章 非線性方程求根····················31.1迭代法··························

2、3;···········31.2牛頓法·····································

3、83;41.3弦截法······································51.4二分法·········&

4、#183;····························6第二章 插值····················

5、···········72.1線性插值····································72.2二次插值&#

6、183;···································82.3拉格朗日插值············

7、3;···················92.4分段線性插值·····························

8、··102.5分段二次插值·······························11第三章 數(shù)值積分·············

9、83;············133.1復(fù)化矩形積分法·····························133.2復(fù)化梯形積分法····

10、83;························143.3辛普森積分法·······················

11、3;·······153.4變步長梯形積分法···························16第四章 線性方程組數(shù)值法···········&

12、#183;······174.1約當(dāng)消去法·································17 4.2高斯消去法······

13、3;··························184.3三角分解法······················

14、···········204.4雅可比迭代法································214.5高斯賽德爾迭代法···

15、·······················23第五章 常積分方程數(shù)值法··················255.1顯示歐拉公式法····

16、3;·························255.2歐拉公式預(yù)測校正法······················&#

17、183;···26 5.3改進(jìn)歐拉公式法······························275.4四階龍格庫塔法············&

18、#183;···············28數(shù)值計算方法第一章 非線性方程求根1.1迭代法程序代碼：Private Sub Command1_Click()x0 = Val(InputBox("請輸入初始值x0")ep = Val(InputBox(請輸入誤差限ep)f = 0While f = 0X1 = (Exp(2 * x0) - x0) / 5If Abs(X1 - x0) < ep ThenPrint X1f

19、= 1Elsex0 = X1End IfWendEnd Sub例：求f(x)=e2x-6x=0在x=0.5附近的根（ep=10-10）1.2牛頓法程序代碼：Private Sub Command1_Click()b = Val(InputBox("請輸入被開方數(shù)x0")ep = Val(InputBox(請輸入誤差限ep)f = 0While f = 0X1 = x0 - (x0 2 - b) / (2 * b)If Abs(X1 - x0) < ep ThenPrint X1f = 1Elsex0 = X1End IfWendEnd Sub例：求的值。（ep=10-

20、10）1.3弦截法程序代碼：Private Sub Command1_Click()x0 = Val(InputBox("請輸入第一個初始值x0")X1 = Val(InputBox("請輸入第二個初始值x1")ep = Val(InputBox("請輸入誤差限ep")f = 0While f = 0X2 = X1 - (X1 8 - 13) * (X1 - x0) / (X1 8 - 13) - (x0 8 - 13)If Abs(X2 - X1) < ep ThenPrint X2f = 1Elsex0 = X1X1 = X

21、2End IfWendEnd Sub例：求f(x)=x8-13的正根（初始值x1=1,x2=10,ep=10-10)1.4二分法程序代碼：Private Sub Command1_Click()a = Val(InputBox("請輸入?yún)^(qū)間端點(diǎn)a")b = Val(InputBox("請輸入?yún)^(qū)間端點(diǎn)b")ep = Val(InputBox("請輸入誤差限ep")f = 0While f = 0x = (a + b) / 2fx = Exp(-x / 7) * (9 - 2 * x) - 8fa = Exp(-a / 7) * (9 -

22、 2 * a) - 8If fx = 0 Thenf = 1Print "方程的根是", xElseIf fa * fx > 0 Thena = xElseb = xEnd IfIf Abs(b - a) < ep Thenx = (b + a) / 2f = 1Print "方程的根是", xEnd IfEnd IfWendEnd Sub例：求方程f（x）=e-7/x(9-2x)-8在區(qū)間0,1內(nèi)的實(shí)根。（ep=10-10）第2章 插 值2.1線性插值程序代碼：Private Sub Command1_Click()X0 = Val(Inp

23、utBox("請輸入第一個結(jié)點(diǎn)X:")Y0 = Val(InputBox("請輸入第一個結(jié)點(diǎn)Y:")X1 = Val(InputBox("請輸入第二個結(jié)點(diǎn)X:")Y1 = Val(InputBox("請輸入第二個結(jié)點(diǎn)Y:")f = 0While f = 0x = Val(InputBox("請輸入未知點(diǎn)的自變量值X:")L0 = (x - X1) / (X0 - X1)L1 = (x - X0) / (X1 - X0)y = L0 * Y0 + L1 * Y1Print "x=&quo

24、t; x, "y=" yf = Val(InputBox("是否繼續(xù)（0/1):")WendEnd Sub例：已知兩點(diǎn)（13 , 1）、（49 , 8），求30處的值。2.2二次插值程序代碼：Private Sub Command1_Click()X0 = Val(InputBox("請輸入第一個結(jié)點(diǎn)X:")Y0 = Val(InputBox("請輸入第一個結(jié)點(diǎn)Y:")X1 = Val(InputBox("請輸入第二個結(jié)點(diǎn)X:")Y1 = Val(InputBox("請輸入第二個結(jié)點(diǎn)Y

25、:")X2 = Val(InputBox("請輸入第三個結(jié)點(diǎn)X:")Y2 = Val(InputBox("請輸入第三個結(jié)點(diǎn)Y:")f = 0While f = 0x = Val(InputBox("請輸入未知點(diǎn)的自變量值X:")L0 = (x - X1) * (x - X2) / (X0 - X1) / (X0 - X2)L1 = (x - X0) * (x - X2) / (X1 - X0) / (X1 - X2)L2 = (x - X0) * (x - X1) / (X2 - X0) / (X2 - X1)y = L0

26、* Y0 + L1 * Y1 + L2 * Y2Print "x=" x, "y=" yf = Val(InputBox("是否繼續(xù)（0/1):")WendEnd Sub例：已知三點(diǎn)（81 ，9）、（100 ，10）、（121 ，10），求98處的值。2.3拉格朗日插值程序代碼：Private Sub Command1_Click()Dim x(), y()n = Val(InputBox("請輸入插值節(jié)點(diǎn)數(shù)N")ReDim x(n), y(n)For i = 0 To nx(i) = Val(InputBox(&

27、quot;請輸入插值節(jié)點(diǎn)x(" + Str(i) + ")")y(i) = Val(InputBox("請輸入插值節(jié)點(diǎn)y(" + Str(i) + ")")Next if = 0While f = 0xx = Val(InputBox("請輸入未知點(diǎn)的自變量x:")Sum = 0For i = 0 To nt = 1For j = 0 To nIf j <> i Thent = t * (xx - x(j) / (x(i) - x(j)End IfNext jSum = Sum + t * y

28、(i)Next iPrint "x=" xx, "y=" Sumf = Val(InputBox("是否繼續(xù)（0/1）")WendEnd Sub例：已知四點(diǎn)（100 ，10）、（81 ，9）、（64 ，8）、（49 ，7），求87 處的值。2.4分段線性插值程序代碼：Private Sub Command1_Click()Dim x(), y()n = Val(InputBox("請輸入插值節(jié)點(diǎn)數(shù)N")ReDim x(n), y(n)For i = 0 To nx(i) = Val(InputBox("請

29、輸入插值節(jié)點(diǎn)x(" + Str(i) + ")")y(i) = Val(InputBox("請輸入插值節(jié)點(diǎn)y(" + Str(i) + ")")Next if = 0While f = 0xx = Val(InputBox("請輸入未知點(diǎn)的自變量x:")L = 0j = 1While L = 0If xx < x(j) Thenk = j + 1L = 1Elsej = j + 1If j > n - 1 Thenk = n - 1L = 1End IfEnd IfWendl0 = (xx -

30、 x(k) / (x(k - 1) - x(k)l1 = (xx - x(k - 1) / (x(k) - x(k - 1)yy = l0 * y(k - 1) + l1 * y(k)Print "x=" xx, "y=" yyf = Val(InputBox("是否繼續(xù)（0/1）")WendEnd Sub例：已知三點(diǎn)（361 , 19）、（324 ，18）、（289 ，17），N=2，求300處的值。2.5分段二次插值程序代碼：Private Sub Command1_Click()Dim x(), y()n = Val(Input

31、Box("請輸入插值節(jié)點(diǎn)數(shù)N")ReDim x(n), y(n)For i = 0 To nx(i) = Val(InputBox("請輸入插值節(jié)點(diǎn)x(" + Str(i) + ")")y(i) = Val(InputBox("請輸入插值節(jié)點(diǎn)y(" + Str(i) + ")")Next if = 0While f = 0xx = Val(InputBox("請輸入未知點(diǎn)的自變量x:")If x0 < x(1) Thenk = 1f = 1End Ifi = 2Do W

32、hile f = 0 And i >= n - 1If x0 < x(i) ThenIf x0 - x(i - 1) < x(i) - x0 Thenk = i - 1f = 1Elsek = if = 1End IfElsei = i + 1End IfLoopIf f = 0 Thenk = n - 1End Ifl1 = (xx - x(k + 1) * (xx - x(k) / (x(k - 1) - x(k + 1) * (x(k - 1) - x(k)l2 = (xx - x(k + 1) * (xx - x(k - 1) / (x(k) - x(k + 1) *

33、 (x(k) - x(k - 1)l3 = (xx - x(k) * (xx - x(k - 1) / (x(k + 1) - x(k) * (x(k + 1) - x(k - 1)yy = l1 * y(k - 1) + l2 * y(k) + l3 * y(k + 1)Print "x=" xx, "y=" yyf = Val(InputBox("是否繼續(xù)（0/1）")WendEnd Sub例：已知三點(diǎn)（225 , 15）、（196 ，14）、（169 ，13），求180處的值。第3章 數(shù)值積分3.1 復(fù)化矩形積分法程序代碼：Pr

34、ivate Sub Command1_Click()a = Val(InputBox("請輸入積分下限a")b = Val(InputBox("請輸入積分上限b")n = Val(InputBox("請輸入積分區(qū)間等分?jǐn)?shù)N")h = (b - a) / nSum = 0For i = 1 To nSum = Sum + (a + (i - 0.5) * h) 2Next ir = h * SumPrint "復(fù)化矩形積分法計算結(jié)果：" rEnd Sub 例：求X2在區(qū)間3,5的積分值，等分區(qū)間為100。3.2復(fù)化梯

35、形積分法程序代碼：Private Sub Command1_Click()a = Val(InputBox("請輸入積分下限a")b = Val(InputBox("請輸入積分上限b")n = Val(InputBox("請輸入積分區(qū)間等分?jǐn)?shù)N")h = (b - a) / nSum = 0For i = 1 To n - 1Sum = Sum + (a + i * h) 2Next it = h * (a 2 + b 2) / 2 + h * SumPrint "復(fù)化梯形積分法計算結(jié)果：" tEnd Sub例：求

36、X2在區(qū)間3,5的積分值，等分區(qū)間為100。3.3辛普生積分法程序代碼：Private Sub Command1_Click()a = Val(InputBox("請輸入積分下限A:")b = Val(InputBox("請輸入積分上限B:")n = Val(InputBox("請輸入積分區(qū)間等分?jǐn)?shù)N:")h = (b - a) / nSum = 0w = a + h / 2While w < bSum = Sum + (w - h / 2) 2 + 4 * w 2 + (w + h / 2) 2w = w + hWends =

37、 Sum * h / 6Print "辛普生積分法計算結(jié)果：" sEnd Sub例：求X2在區(qū)間3,5的積分值，等分區(qū)間為100。3.4變步長梯形積分法程序代碼：Private Sub Command1_Click()a = Val(InputBox("請輸入積分下限a:")b = Val(InputBox("請輸入積分上限b:")ep = Val(InputBox("請輸入誤差限ep:")n = 1h = b - at1 = h * (a 2 + b 2) / 2f = 0While f = 0Sum = 0Fo

38、r i = 1 To n - 1Sum = Sum + (a + (i - 1 / 2) * h) 2Next iT2 = t1 / 2 + h * Sum / 2If Abs(T2 - t1) < ep ThenPrint T2f = 1Elset1 = T2h = h / 2n = 2 * nEnd IfWendEnd Sub例：求X2在區(qū)間3,5的積分值，誤差限ep=0.0001。第4章 線性方程組數(shù)值解法4.1 約當(dāng)消去法程序代碼：Private Sub Command1_Click()Dim a()n = Val(InputBox("請輸入方程的個數(shù)N:")

39、ReDim a(n, n + 1)For i = 1 To nFor j = 1 To n + 1a(i, j) = Val(InputBox("請輸入增廣矩陣A(" + Str(i) + "," + Str(j) + ")=")Next jNext iFor k = 1 To nm = a(k, k)For j = k To n + 1a(k, j) = a(k, j) / mNext jFor i = 1 To nIf i <> k Thenm = a(i, k)For j = k To n + 1a(i, j) =

40、a(i, j) - a(k, j) * mNext jEnd IfNext iNext kFor i = 1 To nPrint "x(" + Str(i) + ")=" a(i, n + 1)Next iEnd Sub例：已知方程組,求X1 X2 X3的值。 X1+ X2+ X3=20 2X1+3X2+ X3=38 X1+4X2+ X3=35 4.2 高斯消去法程序代碼：Private Sub Command1_Click()Dim a(), x()n = Val(InputBox("請輸入方程個數(shù)N:")ReDim a(n, n

41、+ 1), x(n)For i = 1 To nFor j = 1 To n + 1a(i, j) = Val(InputBox("請輸入增廣矩陣A(" + Str(i) + "," + Str(j) + "):")Next jNext iFor k = 1 To n - 1m = a(k, k)For j = k To n + 1a(k, j) = a(k, j) / mNext jFor i = k + 1 To nm = a(i, k)For j = k To n + 1a(i, j) = a(i, j) - a(k, j) *

42、 mNext jNext iNext kx(n) = a(n, n + 1) / a(n, n)For i = n - 1 To 1 Step -1Sum = 0For j = i + 1 To nSum = Sum + a(i, j) * x(j)Next jx(i) = a(i, n + 1) - SumNext iFor i = 1 To nPrint "x(" + Str(i) + ")=" x(i)Next iEnd Sub例：已知方程組,求X1 X2 X3的值。2X1+5X2+ X3=21 4X1+3X2+3X3=31 X1+3X2+2X3=

43、16 4.3 三角分解法程序代碼：Private Sub Command1_Click()Dim a(), b(), l(), u(), x(), y()n = Val(InputBox("請輸入方程個數(shù)N:")ReDim a(n, n), b(n), l(n, n), u(n, n), x(n), y(n)For i = 1 To nFor j = 1 To na(i, j) = Val(InputBox("請輸入系數(shù)矩陣A(" + Str(i) + "," + Str(j) + "):")Next jb(i)

44、= Val(InputBox("請輸入右端常數(shù)項B(" + Str(i) + "):")Next iFor i = 1 To nFor j = 1 To nIf i > j ThenSum = 0For k = 1 To j - 1Sum = Sum + l(i, k) * u(k, j)Next kl(i, j) = (a(i, j) - Sum) / u(j, j)ElseSum = 0For k = 1 To i - 1Sum = Sum + l(i, k) * u(k, j)Next ku(i, j) = a(i, j) - SumEnd

45、IfNext jNext iFor i = 1 To nSum = 0For j = 1 To i - 1Sum = Sum + l(i, j) * y(j)Next jy(i) = b(i) - SumNext iFor i = n To 1 Step -1Sum = 0For j = i + 1 To nSum = Sum + u(i, j) * x(j)Next jx(i) = (y(i) - Sum) / u(i, i)Next iFor i = 1 To nPrint "x(" + Str(i) + ")=" x(i)Next iEnd Sub

46、例：已知方程組,求X1 X2 X3的值。2X1+3X2+4X3=38 X1+7X2+3X3=65 5X1+2X2+ X3=33 4.4 雅可比迭代法程序代碼：Dim a(), b(), x0(), x()n = Val(InputBox("請輸入方程個數(shù)N:")ReDim a(n, n), b(n), x0(n), x(n)ep = Val(InputBox("請輸入誤差限EP:")nmax = Val(InputBox("請輸入最大迭代次數(shù)Nmax:")For i = 1 To nFor j = 1 To na(i, j) = Va

47、l(InputBox("請輸入系數(shù)矩陣A(" + Str(i) + "," + Str(j) + "):")Next jb(i) = Val(InputBox("請輸入右端常數(shù)項B(" + Str(i) + "):")Next iFor i = 1 To nx0(i) = Val(InputBox("請輸入初始解X0(" + Str(i) + "):")Next ik = 0f = 0While f = 0Max = 0For i = 1 To nSum

48、= 0For j = 1 To nSum = Sum + a(i, j) * x0(j)Next jd = (b(i) - Sum) / a(i, i)x(i) = x0(i) + dIf Max < Abs(d) ThenMax = Abs(d)End IfNext ik = k + 1If Max < ep Then For i = 1 To n Print "x(" + Str(i) + ")=" x(i) Next i f = 1Else If k > nmax Then Print "迭代失敗" f = 1

49、 Else For i = 1 To n x0(i) = x(i) Next i End IfEnd IfWendEnd Sub例：已知方程組,求X1 X2 X3 X4的值。（ep=0.0001,最大迭代次數(shù)1000，初始值均為0）7X1+2X2+3X3+ X4=5 X1+5X2+2X3+ X4=42X1+ X2+8X3+3X4=2 X1+4X2+ X3+7X4=74.5 高斯-賽德爾迭代法程序代碼：Private Sub Command1_Click()Dim a(), b(), x()n = Val(InputBox("請輸入方程個數(shù)N:")ep = 0.0001nma

50、x = 10000ReDim a(n, n), b(n), x(n)For i = 1 To nFor j = 1 To na(i, j) = Val(InputBox("請輸入系數(shù)矩陣A(" + Str(i) + "," + Str(j) + "):")Next jb(i) = Val(InputBox("請輸入右端常數(shù)項b(:" + Str(i) + "):")Next iFor i = 1 To nx(i) = Val(InputBox("請輸入初始解X(:" + St

51、r(i) + "):")Next ik = 0f = 0While f = 0Max = 0For i = 1 To nSum = 0For j = 1 To nSum = Sum + a(i, j) * x(j)Next jd = (b(i) - Sum) / a(i, i)x(i) = x(i) + dIf Max < Abs(d) ThenMax = Abs(d)End IfNext ik = k + 1If Max < ep ThenFor i = 1 To nPrint "x(" + Str(i) + ")="

52、x(i)Next if = 1ElseIf k > nmax ThenPrint "迭代失敗"f = 1End IfEnd IfWendEnd Sub例：已知方程組,求X1 X2 X3的值。（初始值均為0）5X1+ X2+2X3=2 X1+3X2+ X3=8 3X1+ X2+7X3=6第5章 常微分方程的數(shù)值解5.1顯示歐拉法程序代碼：Private Sub Command1_Click()x0 = Val(InputBox("請輸入自變量初始值x0")y0 = Val(InputBox("請輸入自變量初始值y0")xn = Val(InputBox("請輸入自變量值終值xn")n = Val(InputBox("請輸入?yún)^(qū)間等分?jǐn)?shù)")h = (xn - x0) / nX1 = x0 + hIf