((-------- USNG R PROJECT -------))) I. Questions

1) What is vector indexing? Write one of the benefits of vector indexing.

2) Let u be the vector of first 29 odd integers. Build a matrix X with X₁₁ = u₁, X₁₂ = u₁ + u₃, X₁₃ = u₁ + u₃ + u₅, X₂₁ = u₁ + u₃ + ... + u₇ , X₂₂ = u₁ + u₃ + ... + u₉, X₂₃ = u₁ + u₃ + ... + u₁₁, ..., X₅₁ = u₁ + u₃ + ... + u₂₅, X₅₂ = u₁ + u₃ + ... + u₂₇, X₅₃ = u₁ + u₃ + ... + u₂₉ . You should not write any loops. You should not hard-code.

3) Build a 23 x 23 identity matrix without calling diag function and writing loops.