Hi everyone, Well its that great time of year....the time of feverishly studying for finals and I have been doing some practice questions and there are a few that I'm stuck on. My first question I am embarassed to ask, it should be so simple, yet I cannot get the right answer. 1) A highway patrol airplane flies 3 km above a level, straight road at a speed of 120 km/hr. The pilot sees an oncoming car and with the radar determines that the line-of-sight distance from the airplane to the car is 5 km and decreasing at the rate of 160 km/hr. Find the car’s speed along the highway So for this I know the answer is 80 km/h because we have the answers provided but still knowing how to actually get the answer would be nice to Anyway, I started off with drawing my diagram , and labelling it with all of the givens. Next I went with pythagoreans theorem x^3 +y^2-=z^2, and differentiated it. At this point I ended up with 4x+(3)(120) =(5)(160) which gives an answer of 110km/h which of course is not right. I know I am just doing something really stupid here but I dont know what . 2) [tex]/int[/tex] abs(3x-2)dx where b=2 and a=0. I thought this could just be done normally but when I did it I didn't get the answer of 10/3. What I did was I took the function and integrated it to get 3x^2/2 -2x, but try as I might I always ended up with 2 as my answer when I put the numbers in. 3) Find the equation of the line through the point (2,7) such that the area in the first quadrant bound by the line, the x-axis and the y-axis is a minimum For this one I quite honestly have no idea of where to even start. The answer is supposed to be y = (-7/2)x +14, I dont really know where to start so if there is anything that could just get me on the right track I would appreciate that. Thanks in advance for any advice, I appreciate it.