00:04
Okay, on this problem, i'm looking at a parametric function, and i need the slope of a tangent line to the curve at t equals negative one and at t equals one.
00:13
So the greatest thing in calculus is that you don't have to eliminate the parameter to answer these kind of questions.
00:20
But for this question, they're going to want us to find the slopes and then show that i get the same result if i do eliminate the parameters.
00:29
So a slope of a tangent line to a curve, in rectangular coordinates we would find d, y, d, x, but we have x and y separately.
00:43
So we need d y, dt, divided by dx, dt, evaluated at t is plus or minus one, two different answers.
00:54
So d y, dt is the derivative of y equals t over two, which is one -half.
01:05
Is the derivative of this function with respect to t, which is 2t.
01:11
So, dy, dx is 1 half divided by 2t or 1 over 4t.
01:22
D y dx at t equals 1, gives me 1 fourth.
01:30
D y d x at t equals negative 1, gives me negative 1 fourth.
01:36
Now over here to the side, i'm going to eliminate the parameters...