Math Problem Statement

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Explain why the point A(1, 1) lies on the curve y = x^3 - x^2 + x. Calculate the gradient of the curve at A. Calculate the equation of the tangent to the curve at A.

Solution

Let's work through each part of this question.

Given: The curve y=x3x2+xy = x^3 - x^2 + x and point A(1,1)A(1,1).

Part (a): Show that A(1,1)A(1, 1) lies on the curve.

To verify that A(1,1)A(1, 1) lies on the curve, substitute x=1x = 1 into the equation of the curve and check if y=1y = 1.

  1. Substitute x=1x = 1 into y=x3x2+xy = x^3 - x^2 + x: y=(1)3(1)2+(1)=11+1=1y = (1)^3 - (1)^2 + (1) = 1 - 1 + 1 = 1
  2. Since y=1y = 1 when x=1x = 1, the point (1,1)(1, 1) lies on the curve.

Part (b): Calculate the gradient of the curve at AA.

To find the gradient of the curve at AA, calculate the derivative dydx\frac{dy}{dx} and evaluate it at x=1x = 1.

  1. Differentiate y=x3x2+xy = x^3 - x^2 + x with respect to xx: dydx=3x22x+1\frac{dy}{dx} = 3x^2 - 2x + 1
  2. Substitute x=1x = 1 into dydx\frac{dy}{dx} to find the gradient at AA: dydxx=1=3(1)22(1)+1=32+1=2\frac{dy}{dx} \Big|_{x=1} = 3(1)^2 - 2(1) + 1 = 3 - 2 + 1 = 2

So, the gradient of the curve at AA is 22.

Part (c): Calculate the equation of the tangent to the curve at AA.

The equation of a tangent line at a point (x1,y1)(x_1, y_1) with gradient mm is given by: yy1=m(xx1)y - y_1 = m(x - x_1)

  1. Here, (x1,y1)=(1,1)(x_1, y_1) = (1, 1) and m=2m = 2.
  2. Substitute these values into the equation of the tangent: y1=2(x1)y - 1 = 2(x - 1)
  3. Simplify the equation: y=2x2+1y = 2x - 2 + 1 y=2x1y = 2x - 1

So, the equation of the tangent to the curve at AA is y=2x1y = 2x - 1.


Would you like more details or have any questions?

Related Questions

  1. How do you find the normal to the curve at a given point?
  2. What does the second derivative tell us about the curve?
  3. How would you find the points where the gradient is zero?
  4. How can you determine if the tangent is horizontal or vertical?
  5. How would you find the equation of a curve if given its derivative?

Tip:

Always check if a point lies on a curve by substituting its coordinates into the curve's equation.

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Math Problem Analysis

Mathematical Concepts

Coordinate Geometry
Differentiation
Equation of a Tangent Line

Formulas

Equation of the tangent: y - y1 = m(x - x1)
Gradient of the curve: dy/dx
y = x^3 - x^2 + x (cubic function)

Theorems

Power Rule for Differentiation

Suitable Grade Level

Grades 11-12