Find an equation of the tangent to the curve at the point corresponding to the given value of the parameter. x = cos(θ) + sin(4θ) y = sin(θ) + cos(4θ) θ = 0

Respuesta :

The line tangent to the curve at [tex](x(0),y(0))[/tex] has slope

[tex]\dfrac{\mathrm dy}{\mathrm dx}\bigg|_{\theta=0}=\dfrac{\mathrm dy}{\mathrm d\theta}\dfrac{\mathrm d\theta}{\mathrm dx}\bigg|_{\theta=0}=\dfrac{\cos\theta-4\sin4\theta}{-\sin\theta+4\cos4\theta}\bigg|_{\theta=0}=\dfrac14[/tex]

Then the tangent line has equation

[tex]y-y(0)=\dfrac14(x-x(0))[/tex]

[tex]y-1=\dfrac14(x-1)[/tex]

[tex]\boxed{y=\dfrac{x+3}4}[/tex]

The equation of the tangent to the curve is [tex](x,y) = (1,1) + \theta\cdot (4,1)[/tex].

Given the parametric equations of a curve, the parametric equation of the line is presented below:

[tex](x,y) = (x(0), y(0)) + \theta \cdot (\Delta x, \Delta y)[/tex] (1)

[tex]m = \frac{\frac{dy}{d\theta} }{\frac{dx}{d\theta} } = \frac{\Delta y}{\Delta x }[/tex] (2)

Where:

  • [tex]\theta[/tex] - Parametric variable.
  • [tex]m[/tex] - Slope at the tangency point.
  • [tex]\Delta x[/tex] - Change in x.
  • [tex]\Delta y[/tex] - Change in y.
  • [tex]x(0)[/tex], [tex]y(0)[/tex] - Coordinates of the tangent line.

The first derivatives of the curve are described below:

[tex]\frac{dx}{d\theta} = -\sin \theta + 4\cdot \cos 4\theta[/tex] (3)

[tex]\frac{dy}{d\theta} = \cos \theta -4\cdot \sin 4\theta[/tex] (4)

If we know that [tex]\theta = 0[/tex], then we have the following expression:

By (3) and (4):

[tex]\frac{dx}{d\theta} = -\sin 0 + 4\cdot \cos (4\cdot 0)[/tex]

[tex]\frac{dx}{d\theta} = 4[/tex]

[tex]\frac{dy}{d\theta} = \cos 0 - 4\cdot \sin (4\cdot 0)[/tex]

[tex]\frac{dy}{d\theta} = 1[/tex]

[tex]m = \frac{1}{4}[/tex]

[tex]\Delta x = 4, \Delta y = 1[/tex]

[tex]x(0) = \cos 0 + \sin (4\cdot 0)[/tex]

[tex]x(0) = 1[/tex]

[tex]y(0) = \sin 0 + \cos (4\cdot 0)[/tex]

[tex]y(0) = 1[/tex]

Hence, the equation of the tangent to the curve is:

[tex](x,y) = (1,1) + \theta\cdot (4,1)[/tex]

We kindly invite to check this question on tangent lines: https://brainly.com/question/15585522