# Finding the limit

• Oct 20th 2009, 05:37 PM
igodspeed
Finding the limit
Hello,
This is a question from a past exam. Any help would be appreciated. What does x(t) and y(t) mean here? http://img3.imageshack.us/img3/9532/bigproblem.th.jpg
Thanks
• Oct 20th 2009, 05:41 PM
mr fantastic
Quote:

Originally Posted by igodspeed
Hello,
This is a question from a past exam. Any help would be appreciated. What does x(t) and y(t) mean here? http://img3.imageshack.us/img3/9532/bigproblem.th.jpg
Thanks

x(t) means that x is a function of t. Ditto y(t). They are parametric equations of a curve.
• Oct 20th 2009, 05:48 PM
igodspeed
If i had to solve just the first part, how would i solve it.
• Oct 20th 2009, 05:54 PM
mr fantastic
Quote:

Originally Posted by igodspeed
I don't get why did you say it is wrong? If i had to solve just this, how would i solve it.

Substitute \$\displaystyle y = mx\$ and try taking the limit as x approaches 0.
• Oct 20th 2009, 05:58 PM
igodspeed
What i did was i substituted y for x and so i got x to the power of 4 and on the bottom i have x squared and x to 6 then when i find the limit, the ans is zero. is this wrong? then on the second one i did the same for y as x=y.
• Oct 20th 2009, 06:02 PM
mr fantastic
Quote:

Originally Posted by igodspeed
perhaps. But what i did was i substituted y for x and so i got x to the power of 4 and on the bottom i have x squared and x to 6 then when i find the limit, the ans is zero. is this wrong? then on the second one i did the same for y as x=y.

The question says for ALL lines passing through the origin. You did it for exactly two such lines.
• Oct 20th 2009, 07:28 PM
igodspeed
ok i solved it. now i got the value for m and n so could can i write it parametically? 2rd question?
• Oct 20th 2009, 07:54 PM
mr fantastic
Quote:

Originally Posted by igodspeed
ok i solved it. now i got the value for m and n so could can i write it parametically? 2rd question?

What have you done? Have you substituted the expressions for x and y into the function? Simplified? etc.