Publications by Farhana Zahir
FZahirDiscussion4
Problem C25 page 443 Define the linear transformation \[T:\mathbb{C}^3 \rightarrow \mathbb{C}^2, T \bigg(\begin{vmatrix}x_1\\x_2\\x_3\end{vmatrix}\bigg)=\begin{vmatrix} 2x_1-x_2+5x_3 \\ -4x_1+2x_2-10x_3\end{vmatrix}\] Verify that T is a linear transformation Solution: If T is a linear transformation and a and b are vectors and c is a scaler, then...
1176 sym
Data608Assignment01
Principles of Data Visualization and Introduction to ggplot2 I have provided you with data about the 5,000 fastest growing companies in the US, as compiled by Inc. magazine. lets read this in: inc <- read.csv("https://raw.githubusercontent.com/charleyferrari/CUNY_DATA_608/master/module1/Data/inc5000_data.csv", header= TRUE) And lets preview this...
2935 sym R (6176 sym/16 pcs) 4 img
FZahirDiscussion3
Problem C10 page 388 Find the charactertistic polynomial of the matrix library(knitr) library(pracma) A = matrix(c (1,2,3,4), nrow=2, byrow=T) print(A) ## [,1] [,2] ## [1,] 1 2 ## [2,] 3 4 Solution using R charpoly(A) ## [1] 1 -5 -2 This gives us the characteristic polynomial as below: \[{ PA(x)=λ}^{ 2 }-5{ λ } -2\] Solu...
790 sym R (162 sym/5 pcs)
Data 605 Assignment 02
Problem Set 1 Show that ATA!=AAT in general. (Proof and demonstration) #Let us take a 4X3 matrix mat1 mat1<-matrix(1:12,nrow=4, byrow=T) mat1 ## [,1] [,2] [,3] ## [1,] 1 2 3 ## [2,] 4 5 6 ## [3,] 7 8 9 ## [4,] 10 11 12 #Calculate the transpose of mat1, this is a 3X4 matrix mat1_transpose<-t(mat1) ma...
831 sym R (4000 sym/39 pcs)
FZahirDiscussion2Response
Constructing the matrix and calculating determinant A <- matrix(c(1, 2, 1, 2, 0, 1, 2, 3, 7/4), nrow=3, byrow=T) A ## [,1] [,2] [,3] ## [1,] 1 2 1.00 ## [2,] 2 0 1.00 ## [3,] 2 3 1.75 print(det(A)) ## [1] 0 Trying to find inverse using solve print(solve(A)) ##Error: Lapack routine dgesv: system is exactly singular: U[3...
396 sym R (634 sym/10 pcs)
FZahirDiscussion2
Ex C25 Pg 353 Calculating determinant of a 3 X 3 matrix Doing the computations by hand, find the determinant of the matrix below: mat = matrix(c (3,-1,4,2,5,1,2,0,6), ncol=3 , nrow=3, byrow=TRUE) mat ## [,1] [,2] [,3] ## [1,] 3 -1 4 ## [2,] 2 5 1 ## [3,] 2 0 6 Steps to calculate the determinant of the 3 X 3 matr...
343 sym R (978 sym/12 pcs)
Data605HW01
Problem 01 (1) Calculate the dot product u:v where u = [0.5;0.5] and v= [3;-4] u <- c(0.5,0.5) v <- c(3,-4) ##Dot product without using R function dotprod<-u[1]*v[1]+u[2]*v[2] dotprod ## [1] -0.5 ##Dot product using R function library('pracma') dotprod1<-dot(u,v) dotprod1 ## [1] -0.5 (2) What are the lengths of u and v? ##Length u len_...
449 sym R (2745 sym/16 pcs)
Data605Discussion1response
Problem 3 page 41 Using R to build the matrix a<-matrix(c(2,3,-1,0,1,2,1,3,1,3,3,7), nrow=3, byrow=TRUE) a ## [,1] [,2] [,3] [,4] ## [1,] 2 3 -1 0 ## [2,] 1 2 1 3 ## [3,] 1 3 3 7 b<-matrix(c(0,3,7),nrow=3) b ## [,1] ## [1,] 0 ## [2,] 3 ## [3,] 7 Results: X1=1, X2=0, X3=2 Row echelon us...
147 sym R (717 sym/12 pcs)
Data605Discussion01
Matrix Multiplication Ex C26, page 191, A first Course in Linear Algebra, Beezer Question: Compute the product AB of the two matrices below using Matrix Multiplication(MM) Constructing the matrix A<-matrix(c(1,3,1,0,1,0,1,1,2),nrow=3,byrow=TRUE) A ## [,1] [,2] [,3] ## [1,] 1 3 1 ## [2,] 0 1 0 ## [3,] 1 1 2 B<...
635 sym R (1115 sym/10 pcs)
Final Project
Introduction This project looks at the relationship between daily stock returns and mean twitter sentiment scores.There are lots of research article on the web about the relationship between social media sentiments and stock prices. In this project, we have tried to identify whether there is any relationship between daily returns for three tech s...
7940 sym R (11233 sym/46 pcs) 7 img