mat267_19527S19
Thursday, May 9, 2019
Tuesday, April 30, 2019
Thursday, April 25, 2019
A practice final exam for tomorrow
Practice Final
Here's a practice final. I suggest you take an hour to work the problems before you go to class tomorow.
Here's a practice final. I suggest you take an hour to work the problems before you go to class tomorow.
Tuesday, April 23, 2019
Current scores and estimated grades
The estimated score is based on extrapolating your final exam score as the average of your exam scores to date. The estimated flat and curved grades are determined from the estimated score using according to the grade templates described in the course syllabus.
Monday, April 22, 2019
Sunday, April 21, 2019
13.4#5
Hello Professor,
You asked me to email you about this question so you could explain it on the blog.
Much Appreciated,

*********************************
You asked me to email you about this question so you could explain it on the blog.
Much Appreciated,

*********************************
Ah. This is a different problem than the one I thought we were talking about. Notice that the problem says that the path is "nonclosed"? This means that you don't have a closed loop, just the three line segments AB+BC+CD, but you don't have DA also, so Green's theorem doesn't directly apply. You could solve this problem directly just by integrating F=<sin(x)+3y, 2x+y> and integrating
∫ F.dr_1 + ∫ F.dr_2 + ∫ F.dr_3 where r_1(t)=t*<2,2> for 0≤t≤1, r_2(t)=(1-t)*<2,2> + t*<2,4> for 0≤t≤1, r_3(t)=(1-t)*<2,4> + t*<0,6> for 0≤t≤1. Or you *could* still use Green's theorem if you're willing to be a little sneaky: since ∂F_2/∂x = 2 and ∂F_1/∂y = 3, Green's theorem implies that
∬_D (-1)dA - ∫ F.dr_4 = ∫ F.dr_1 + ∫ F.dr_2 + ∫ F.dr_3 , where D is the enclosed region and where r_4(t)=(1-t)*<0,6> . This is a little bit easier approach since ∬_D (-1)dA = -Area = -8, and
r'_4(t)= -<0,6> so ∫ F.dr_4 = ∫_0^1<18(1-t), 6(1-t)>.<0, -6> dt = -36 ∫_0^1(1-t) dt.
∫ F.dr_1 + ∫ F.dr_2 + ∫ F.dr_3 where r_1(t)=t*<2,2> for 0≤t≤1, r_2(t)=(1-t)*<2,2> + t*<2,4> for 0≤t≤1, r_3(t)=(1-t)*<2,4> + t*<0,6> for 0≤t≤1. Or you *could* still use Green's theorem if you're willing to be a little sneaky: since ∂F_2/∂x = 2 and ∂F_1/∂y = 3, Green's theorem implies that
∬_D (-1)dA - ∫ F.dr_4 = ∫ F.dr_1 + ∫ F.dr_2 + ∫ F.dr_3 , where D is the enclosed region and where r_4(t)=(1-t)*<0,6> . This is a little bit easier approach since ∬_D (-1)dA = -Area = -8, and
r'_4(t)= -<0,6> so ∫ F.dr_4 = ∫_0^1<18(1-t), 6(1-t)>.<0, -6> dt = -36 ∫_0^1(1-t) dt.
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