Should I ask for another letter of rec?

<p>I am applying to the college of engineering and have a letter of rec from my math (pre-calc and AP Calc BC) teacher and one from my spanish teacher (3 years, in AP now). Both should be really good. I remember hearing that for engineering Cornell wants recs from math and science teachers. I know it is getting kind of late to ask but is it worth it to ask my AP Bio or AP Chem teachers for one?</p>