我一直試圖圍繞這個問題來解決這個問題,但不幸的是我對積分和R都很陌生。誰能幫我弄清楚我在這裏可能會做錯什麼?問題如下: Question 3R中的基本集成過程
這裏是我到目前爲止的代碼:
## Question 3
rm(list=ls())
## a)
X<-(2*(1:20))
X
## b)
Y<-rep(0,20)
Y
## c)
for (k in 1:20){
Y[k] <- k
if (k < 12){
Y[k]<-cos(3*k)
} else if (k >= 12) {
integral <- function(t) sqrt(t)
Y[k]<-integrate(integral, lower = 0, upper = k)
}
}
Y
這裏是我的輸出,當我運行代碼:
Warning messages:
1: In Y[k] <- integrate(integral, lower = 0, upper = k) :
number of items to replace is not a multiple of replacement length
2: In Y[k] <- integrate(integral, lower = 0, upper = k) :
number of items to replace is not a multiple of replacement length
3: In Y[k] <- integrate(integral, lower = 0, upper = k) :
number of items to replace is not a multiple of replacement length
4: In Y[k] <- integrate(integral, lower = 0, upper = k) :
number of items to replace is not a multiple of replacement length
5: In Y[k] <- integrate(integral, lower = 0, upper = k) :
number of items to replace is not a multiple of replacement length
6: In Y[k] <- integrate(integral, lower = 0, upper = k) :
number of items to replace is not a multiple of replacement length
7: In Y[k] <- integrate(integral, lower = 0, upper = k) :
number of items to replace is not a multiple of replacement length
8: In Y[k] <- integrate(integral, lower = 0, upper = k) :
number of items to replace is not a multiple of replacement length
9: In Y[k] <- integrate(integral, lower = 0, upper = k) :
number of items to replace is not a multiple of replacement length
> Y
[[1]]
[1] -0.9899925
[[2]]
[1] 0.9601703
[[3]]
[1] -0.9111303
[[4]]
[1] 0.843854
[[5]]
[1] -0.7596879
[[6]]
[1] 0.6603167
[[7]]
[1] -0.5477293
[[8]]
[1] 0.424179
[[9]]
[1] -0.2921388
[[10]]
[1] 0.1542514
[[11]]
[1] -0.01327675
[[12]]
[1] 27.71282
[[13]]
[1] 31.24811
[[14]]
[1] 34.92214
[[15]]
[1] 38.72984
[[16]]
[1] 42.66667
[[17]]
[1] 46.72854
[[18]]
[1] 50.91169
[[19]]
[1] 55.21273
[[20]]
[1] 59.62849
我對B值)似乎不正確使用計算器檢查結果時,我不知道爲什麼我收到c)的警告。我也不熟悉積分,所以我不知道我應該期待什麼樣的價值觀。感謝您提供任何幫助!
您可能會發現使用一個簡單的表達式來計算t ^(1/2)的積分在適當的限制條件下評估是有幫助的。該問題沒有具體說明你必須使用R代碼來評估積分。 – Robert
謝謝我欣賞幫助! –