Math Journal #2:

1) Question #7 Page 567:

This question was very easy, because I mainly needed to graph the 3 equations and these were not too hard. The first equation I need to graph  was Y=2 and this was just a straight line with range of 2 and domain of XER. The next equation I needed to graph was Y = 2x – 4 which was also very easy because in that equation M(Slope) = 2 and B(Y-Int) = -4 so I just had to put a point on -4 and then I could easily draw the rest of the graph with a rise of 2 and a run of 1. The last equation was Y=-5 and this was very simple to graph because again I just had to draw a straight line with range of -5 and domain of XER. I feel very comfortable to do more questions like this, because I found this unit quite easy. During this question I was very calm and not stressed out or rushing because the question was very simple. This type of question is very important though because it combines many basics of using a graph and understanding equations that are necessary building blocks for further progression in Linear Relations units. I checked my answers in the answer key and I got everything correct on the first try.

2) When you are trying to find the Y Intercept you set the X Intercept to 0.  When you are trying to find the X Intercept you set the Y Intercept to 0. You use this method because whenever the line segment crosses over an axis the coordinate of the other axis will be 0. For example if a line segment has an X Intercept of 5 then that means the coordinates of the point on the line where X = 5 will be (5,0), because when the line segment is at 5 on the X Intercept then Y = 0.

3) Question #8 Page 605:

When I first looked at this question it seemed very confusing, but after a reading it over a couple times the solution became clear to me. I was easily able to find that after 4 days if the water dropped 0.6 meters then the water was dropping 0.15 meters per day. I found this by subtracting 2.25 from 2.85 to get 0.6. I then divided 0.6 by 4 (days) which gave me the answer of 0.15. For part A I needed to find a function that represented the question and I knew that if Height = h and Time (days) = T then the function would be h(t) = 2.85 – 0.15t because the height begins at 2.85 meters above sea level and every day (t) the water drops 0.15 meters. For part B I needed to state the slope and this was simple because I had already needed to find the slope for question A which M = -0.15. The slope in this function represents the change of water level per day. For part C I needed to find the domain and range for h. The domain = time so I divided 2.85/0.15 to get 19 (it would take 19 days to get the water back to normal level. This means domain: {0<t<19} (if </> = greater/less than or equal to). The range = height so the max height is 2.85 and the minimum height is 0 so therefore range: {0<h<2.85}. I felt comfortable doing this question because I just needed to take my time and think things through and I was easily able to get the answer. I liked this question because most of the linear relations unit is quite easy, but this section of it (slope as rate of change) is a bit more of a challenge and I enjoy that.

By Trevor Thirsk.