ATAR Notes: Forum
VCE Stuff => VCE Mathematics => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Specialist Mathematics => Topic started by: eilatan on November 07, 2008, 04:26:23 pm
-
Ok so I'm working through the long answer questions of the MAV 2006 practice exam 2 and have come across a problem in understanding how they have gotten a solution to question 2c)ii (for those playing at home).
I get how they've made the j component of r = 0 to find when the stone hits the ground but to do that they suggest graphing the j component 
into the calculator. I graphed it as a funtion then as a parametric but I don't get the same shape/answer as they've put in their solutions.
Please help! Am I graphing it wrong?
-
i dont see why you need to graph it, but maybe your getting the wrong graph because it is in radian mode?
to get the answer i think you would need to sub in the value for t that u obtained from the j=0 part and sub that into the i component
-
Well the solutions suggested I graph it so I tried but it didn't work. My calc was in radian mode when I tried to graph it because of the sine. (It is supposed to be in radian mode yes?)
I just tried to solve for t without graphing it and used the quadratic formula and it worked. Thanks anyhow...but time for the next question/problem I have:
Q4a)
Solution's saying that the arc of the bowl can be modelled as parabola 
and in actual question asks to show that 
. Solutions then say that it is obvious that b=0 due to the symmetry of the parabola. Can someone please explain to me how that is obvious?...Thanks.
-
Nope, it is suppose to be in degree mode.(You usually use radian mode when dealing with trig fuctions but in this case you have to use degree as you are dealing with degrees)
-
OH ok. So if the question gives you the angle in degrees you have to graph it in degree mode...right.
Can someone please answer my 2nd question as mentioned above...?