Math Problem Statement

a curve is such that dy/dx=6/(3x-2)^3 and A(1,-3) lies on the curve. a point is moving along the curve and at A the y coordinate of the point is increasing at 3 units per second. find the rate of increase at A of the x coordinate of the point

Solution

To find the rate of increase of the xx-coordinate at point A(1,3)A(1, -3), given the differential equation of the curve and the information about the rate of change of the yy-coordinate, we need to use the following approach.

Step 1: Understand the given information

We are given:

  • The slope of the curve is dydx=6(3x2)3\frac{dy}{dx} = \frac{6}{(3x - 2)^3}.
  • At point A(1,3)A(1, -3), the rate of change of the yy-coordinate, dydt\frac{dy}{dt}, is 33 units per second.

We need to find dxdt\frac{dx}{dt} at AA.

Step 2: Chain rule relation between dxdt\frac{dx}{dt} and dydt\frac{dy}{dt}

By the chain rule, we know: dydt=dydxdxdt\frac{dy}{dt} = \frac{dy}{dx} \cdot \frac{dx}{dt} This equation connects the rate of change of yy with respect to time tt, to the rate of change of xx with respect to time tt. We can rearrange this to solve for dxdt\frac{dx}{dt}: dxdt=dydt÷dydx\frac{dx}{dt} = \frac{dy}{dt} \div \frac{dy}{dx}

Step 3: Substitute known values

At point A(1,3)A(1, -3), we are given dydt=3\frac{dy}{dt} = 3. We need to find dydx\frac{dy}{dx} at x=1x = 1. Using the equation for dydx\frac{dy}{dx}: dydx=6(3x2)3\frac{dy}{dx} = \frac{6}{(3x - 2)^3} Substitute x=1x = 1: dydx=6(3(1)2)3=6(32)3=613=6\frac{dy}{dx} = \frac{6}{(3(1) - 2)^3} = \frac{6}{(3 - 2)^3} = \frac{6}{1^3} = 6

Step 4: Calculate dxdt\frac{dx}{dt}

Now, substitute dydt=3\frac{dy}{dt} = 3 and dydx=6\frac{dy}{dx} = 6 into the chain rule equation: dxdt=36=12\frac{dx}{dt} = \frac{3}{6} = \frac{1}{2}

Thus, the rate of increase of the xx-coordinate at point AA is 12\frac{1}{2} units per second.


Would you like further details or clarification?

Here are 5 related questions to consider:

  1. How would the rate of change dxdt\frac{dx}{dt} vary if dydt\frac{dy}{dt} were different?
  2. Can you find the equation of the curve by integrating the slope dydx\frac{dy}{dx}?
  3. How would you handle the case if dydx\frac{dy}{dx} were more complex, involving trigonometric functions?
  4. What happens to dxdt\frac{dx}{dt} if the slope dydx\frac{dy}{dx} approaches zero?
  5. How can implicit differentiation be applied to problems like this in more complex curves?

Tip: Always apply the chain rule when differentiating a function with respect to time, especially when dealing with rates of change in multiple variables.

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Math Problem Analysis

Mathematical Concepts

Differentiation
Chain Rule
Rates of Change

Formulas

dy/dx = 6 / (3x - 2)^3
dy/dt = dy/dx * dx/dt
dx/dt = dy/dt ÷ dy/dx

Theorems

Chain Rule

Suitable Grade Level

Grades 11-12