How fast was the 30-year fixed mortgage rate decreasing in the first week of May in 2011 (t = 1)? (Round your answer to two decimal places.)

Question

Mortgage Rates

 The average 30-year fixed mortgage rate in the United States in the first week of May in 2010 through 2012 is approximated by

M(t)= 55.9 / t^2-0.31t+11.2

percent per year. Here t is measured in years, with t = 0

 corresponding to the first week of May in 2010.

Answer 1

Hi Ryan N.,

So, the rate of change of the Mortgage Rate. I suppose that that should be a change, as a flat percentage rate.

You need the first derivative of the function M(t) = 55.9 / (t^2-0.31t+11.2) with respect to t, I suppose, although the way you wrote your formula would better support M(t) = (55.9/t^2) -0.31t + 11.2 ? Which runs well-nigh unto 5600% per annum during the first month?

Well, you decide what your equation was supposed to be, and comment to correct it. Then we can help?

-- Cheers, -- Mr. d.