Hello; I have a function with 3 variables. I would like to take integration with respect to just one variable. How can I write this function? You can find my function above. ( I am trying to find \int_ZL^ZU rho.bisquare(rho*z+u*sqrt(1-rho^2)*dnorm(u)du.Integrand has three variables, I know the value of k and alpha, I am trying to obtain term2 function with variable z. I want to take integral with respect to u. ) rho.bisquare <- function(x,k = k){ i1 <- abs(x)<=k i2 <- i1==F out <- (x^2/2)*(1-x^2/k^2 + x^4/(3*k^4))*i1 + k^2/6*i2 out } term2<-function(z,k=k,alpha=alpha,rho){ integrand <-function(u){ A <-rho*z+u*sqrt(1-rho^2) out<-rho.bisquare(A/sqrt(3/2),k = k)*dnorm(u) out} ZU <-(sqrt(3/2)*k-rho*z)/sqrt(1-rho^2) ZL <-(-sqrt(3/2)*k-rho*z)/sqrt(1-rho^2) out <-integrate(integrand,lower=ZL,upper=ZU)$value out} Thank you in advance; Derya [[alternative HTML version deleted]]