Math Problem Statement

work out the coordinates of the turning point of the curve y=7x-x^2-5. give any fractions in their simplest forms

Solution

The equation of the curve is y=7xx25y = 7x - x^2 - 5.

To find the turning point, we first differentiate the equation to obtain the gradient function and then solve for xx when the gradient is zero (since the turning point occurs when the gradient is zero).

  1. Differentiate y=7xx25y = 7x - x^2 - 5 with respect to xx: dydx=72x\frac{dy}{dx} = 7 - 2x

  2. Set the derivative equal to zero to find the xx-coordinate of the turning point: 72x=07 - 2x = 0 2x=72x = 7 x=72x = \frac{7}{2}

  3. Substitute x=72x = \frac{7}{2} back into the original equation to find the corresponding yy-coordinate: y=7(72)(72)25y = 7\left(\frac{7}{2}\right) - \left(\frac{7}{2}\right)^2 - 5 y=4924945y = \frac{49}{2} - \frac{49}{4} - 5 To simplify, express all terms with a common denominator of 4: y=984494204y = \frac{98}{4} - \frac{49}{4} - \frac{20}{4} y=9849204y = \frac{98 - 49 - 20}{4} y=294y = \frac{29}{4}

Thus, the coordinates of the turning point are: (72,294)\left( \frac{7}{2}, \frac{29}{4} \right)

Would you like further details or have any questions?

Here are 5 related questions for further exploration:

  1. How do you determine whether the turning point is a maximum or minimum?
  2. Can you sketch the graph of this quadratic equation?
  3. What are the roots of the equation 7xx25=07x - x^2 - 5 = 0?
  4. How does completing the square help in finding the turning point of a quadratic function?
  5. How would the turning point change if the equation were y=7x2x25y = 7x - 2x^2 - 5?

Tip: The second derivative of a function helps determine whether a turning point is a maximum or a minimum.

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Math Problem Analysis

Mathematical Concepts

Calculus
Quadratic Functions
Differentiation
Turning Points

Formulas

First derivative: dy/dx = 7 - 2x
Set derivative to zero to find turning point: 7 - 2x = 0
Substitute x into the original function to find y

Theorems

First Derivative Test

Suitable Grade Level

Grades 10-12