1樓：新新菜鳥手
function sum(byval n as integer) as string
dim i as integer
dim a as double
dim b as integer
b = 1
if n < 2 then
sum = 1
exit function
end if
for i = 2 to n
b = b + i
a = a + cdbl(1 / b)
next i
sum = format(a, "#.0000")end function
private sub command1_click()msgbox sum(6)
end sub
參考這個，希望可以幫到你
2樓：杜守龍
private sub command1_click()dim n as integer, i as integer, mysum as single, p as single
n = val(inputbox("請輸入一個數："))for i = 1 to n
mysum = mysum + i
p = format((1 / (mysum + i + 1)), "0.0000")
next i
msgbox p
end sub
3樓：匿名使用者
function sum(num as integer)sum=(1+num)*num/2
end function
private sub command1_click()dim i as integer
dim s as double
s=0for i=1 to n
s=s+1/sum(i+1)
next
msgbox round(s,4)
end sub
private sub command2_click()dim i as integer
for i=1 to n
msgbox round(1/sum(i+1),4)end sub
編寫vb程式,求數列的前n項之和:s=2/1+3/2+5/3+8/5+13/8…
4樓：匿名使用者
private sub command1_click()dim n as integer
n = inputbox("輸入n值")
dim a1 as double
dim a2 as double
dim a as double
dim sum as double
a1 = 1
a2 = 1
for i = 1 to n
t = a1 + a2
a1 = a2
a2 = t
a = a2 / a1
sum = sum + a
next i
print "數列前" & n & "項和為" & sumend sub
5樓：匿名使用者
這是數學問題哦,所以程式設計要有一定的數學知識的,要找出通項,在用迴圈做.
規律:分母的n+2項是前兩項的和,分子的n項是分母的n+1項,
先設定第一項和第二項的值,第三項就可以用公式計算了.
6樓：唸尐憂
建立兩個文字框,text1＆text2.一個按鈕,command1.
text1為n值.
text2為要求的結果.
command1為計算功能
private sub command1_click()dim a as integer, b as integer, c as integer, i as integer, x as integer, y as integer, z as integer, n as integer, sum as double
n = text1.text
a = 2
b = 3
x = 1
y = 2
select case n
case is = 1
sum = 2
case is = 2
sum = 3.5
case is > 2
sum = 3.5
for i = 3 to n
c = a + b
a = b
b = c
z = x + y
x = y
y = z
sum = sum + c / z
next i
end select
text2.text = sum
end sub
private sub form_load()text1.text = ""
text2.text = ""
end sub
7樓：匿名使用者
三個text , 一個button
private sub command1_click()dim i as integer
dim n as integer
dim dret as double
dim mn as double
dim kn as double
dim t as double
dim s as string
n = text1.text
mn = 2
kn = 1
dret = 0
for i = 1 to n
dret = dret + mn / kns = s & " + " & mn & "/" & knt = mn
mn = mn + kn
kn = t
next i
text2.text = s
text3.text = dret
end sub
vb題用遞迴 方法求數列前n項和 100
8樓：酒瓶裡的蚊子
form1上放一個文字框text1, 一個按鈕command1。
在框中輸入某個數字，例如10，**會將列出f(1)至f(10）的回值。如果你只需要特定的第n項，
答比如第8項，就直接呼叫digui(8)即可。
**：private sub command1_click()dim n as long
n = cint(text1.text)
form1.cls
for n = 1 to 10
print "f(" & cstr(n) & ")=" & digui(n):
next
end sub
private function digui(byval n as integer) as long
select case n
case 1
digui = 0
case 2
digui = 1
case else
digui = 2 * digui(n - 1) - digui(n - 2)
end select
end function
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