摘要：#3.8x <- seq(-2,3,0.05);y <- seq(-1,7,0.05)f <- function(x,y){x^4-2*x^2*y+x^2-2*x*y+4.5*x-4*y+4}z <- outer(x,y,f)par(mfrow = c(1,2))contour(x,y,z,leve... 阅读全文

摘要：# 2.1x <- c(1,2,3);y <- c(4,5,6)e <- c(1,1,1)#1)z <- 2*x+y+e;z#2)crossprod(x,y)#3)outer(x,y)#2.2#按列输入（默认）A <- matrix(1:20,c(4,5))#按行输入B <- matrix(1:20... 阅读全文