Math Problem Statement

Find an equation of the tangent to the curve at the point corresponding to the given value of the parameter: x = t - t^(-1), y = 7 + t^2, t = 1.

Solution

To find the equation of the tangent to the curve at the given point, let's go through the steps. We have the parametric equations:

x=tt1andy=7+t2x = t - t^{-1} \quad \text{and} \quad y = 7 + t^2 at t=1t = 1.

Step 1: Find the point on the curve at t=1t = 1

Substitute t=1t = 1 into the equations for xx and yy:

x=111=11=0x = 1 - 1^{-1} = 1 - 1 = 0 y=7+12=7+1=8y = 7 + 1^2 = 7 + 1 = 8

So, the point on the curve when t=1t = 1 is (0,8)(0, 8).

Step 2: Find dxdt\frac{dx}{dt} and dydt\frac{dy}{dt}

Calculate the derivatives of xx and yy with respect to tt:

dxdt=1+t2=1+1t2\frac{dx}{dt} = 1 + t^{-2} = 1 + \frac{1}{t^2} dydt=2t\frac{dy}{dt} = 2t

Step 3: Evaluate the derivatives at t=1t = 1

Now substitute t=1t = 1 into dxdt\frac{dx}{dt} and dydt\frac{dy}{dt}:

dxdtt=1=1+112=1+1=2\frac{dx}{dt}\Big|_{t=1} = 1 + \frac{1}{1^2} = 1 + 1 = 2 dydtt=1=2×1=2\frac{dy}{dt}\Big|_{t=1} = 2 \times 1 = 2

Step 4: Find the slope of the tangent line dydx\frac{dy}{dx}

The slope of the tangent line is given by:

dydx=dydtdxdt=22=1\frac{dy}{dx} = \frac{\frac{dy}{dt}}{\frac{dx}{dt}} = \frac{2}{2} = 1

Step 5: Write the equation of the tangent line

Using the point-slope form of a line, yy1=m(xx1)y - y_1 = m(x - x_1), with m=1m = 1 and the point (0,8)(0, 8):

y8=1(x0)y - 8 = 1(x - 0) y=x+8y = x + 8

Final Answer:

The equation of the tangent line to the curve at t=1t = 1 is:

y=x+8y = x + 8

Would you like further details or have any questions?

Here are some related questions to consider:

  1. How would the tangent line change if the parameter tt was different?
  2. What are the geometric interpretations of the parametric derivatives dxdt\frac{dx}{dt} and dydt\frac{dy}{dt}?
  3. How does the tangent line relate to the rate of change of the curve at a point?
  4. Could we use implicit differentiation if the curve wasn't in parametric form?
  5. How does changing the parametric equations affect the curve's shape and tangent properties?

Tip: Always double-check your derivative calculations, especially with parametric equations, as errors there can lead to incorrect slopes.

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Math Problem Analysis

Mathematical Concepts

Calculus
Parametric Equations
Derivatives
Tangent Line

Formulas

Point-slope form of a line: y - y1 = m(x - x1)
Derivative of a function with respect to a parameter

Theorems

Derivative of a parametric curve

Suitable Grade Level

Grades 11-12