3. For upper triangular matrices A, B ERnxn, we can have better (i.e. smaller) flop count for computing matrix product C AB by only considering nonzero elements (a) Write a summation expression of Cij that includes only nonzero elements of A and B. tb) Based on thi espeso comethe oduct c) Estimate the number of flops the algorithm requires and compare it with the flop count required for the general case. Hint: These formulas are useful when determining the flop count: n(n1 2 n(n+1)(n+2 6 i-1