Find parametric equations for the tangent line to the curve with the given parametric equations at the specified point.
x = 1 + 2√t, y = t3 - t, z = t3 + t; (3,0,2)

Respuesta :

Solution :

Given parametric equation for :

[tex]$x=1+2 \sqrt t$[/tex]

[tex]$y=t^3-t$[/tex]

[tex]z=t^3+t[/tex]

The point is (3, 0, 2)

The vector equation is equal to :

[tex]$r(t) = \left<1+2 \sqrt t, t^3 -t, t^3+t \right>$[/tex]

Solving for r'(t) by differentiating each of the components of r(t) w.r.t. to t,

[tex]$r'(t)= \left< \frac{1}{\sqrt t}, \ 3t^2-1, \ 3t^2+1 \right>$[/tex]

The parameter value corresponding to (3, 0, 2) is t = 1. Putting in t=1 into r'(t) to solve for r'(t), we get

[tex]$r'(1) = \left< \frac{1}{\sqrt 1}, \ 3(1)^2-1, \ 3(1)^2+1 \right>$[/tex]

We know that parametric equation for  line through the point [tex]$(x_0, y_0, z_0)$[/tex]  and parallel to the direction vector <a, b, c > are

[tex]$x=x_0+at$[/tex]

[tex]$y=y_0+bt$[/tex]

[tex]z=z_0+ct[/tex]

Now substituting the  [tex]$(x_0, y_0, z_0)$[/tex]   = (3, 0, 2) and  <a, b, c > into x, y and z, respectively to solve for the parametric equation of the tangent line to the curve, we get:

[tex]$x=3+(1)t$[/tex]

x  = 3 + t

y = (0) + (2)t

y = 2t

z = (2) + (4)t

z = 2 + 4t