Suppose the matrix A is n × n, positive definite, and banded with bandwidth q = 5. Suppose the vector b is zero except for nonzero entries in three consecutive locations, say bk, bk+1, and bk+2. How...

Suppose the matrix A is n × n, positive definite, and banded with bandwidth q = 5. Suppose the vector b is zero except for nonzero entries in three consecutive locations, say bk, bk+1, and bk+2. How much work does it take to compute bT A−1 b? Can you do it in less than O(n3) flops?