Math Problem Statement

What is the range of this quadratic function?

y

=

x

2

3

x

10

Solution

To find the range of the quadratic function y=x2+3x10y = x^2 + 3x - 10, we need to determine the minimum or maximum value of the function, depending on its orientation, and then analyze the behavior of the function as xx tends to infinity or negative infinity.

Step 1: Identify the orientation of the parabola

The quadratic function y=ax2+bx+cy = ax^2 + bx + c opens upwards if a>0a > 0 and downwards if a<0a < 0. In this case, a=1a = 1 (since the coefficient of x2x^2 is 1), so the parabola opens upwards.

Step 2: Find the vertex

The vertex of the parabola is the point where the function reaches its minimum value (since it opens upwards). The xx-coordinate of the vertex can be found using the formula:

x=b2ax = -\frac{b}{2a}

Here, a=1a = 1 and b=3b = 3. Substituting these values:

x=32(1)=32x = -\frac{3}{2(1)} = -\frac{3}{2}

Now, substitute this xx-value back into the original function to find the corresponding yy-value:

y=(32)2+3(32)10y = \left(-\frac{3}{2}\right)^2 + 3\left(-\frac{3}{2}\right) - 10

y=949210y = \frac{9}{4} - \frac{9}{2} - 10

y=94184404=918404=494y = \frac{9}{4} - \frac{18}{4} - \frac{40}{4} = \frac{9 - 18 - 40}{4} = \frac{-49}{4}

So, the vertex of the parabola is at (32,494)\left(-\frac{3}{2}, -\frac{49}{4}\right).

Step 3: Determine the range

Since the parabola opens upwards and the minimum value of yy is 494-\frac{49}{4}, the range of the function is:

Range=[494,)\text{Range} = \left[-\frac{49}{4}, \infty\right)

Final Answer:

The range of the quadratic function y=x2+3x10y = x^2 + 3x - 10 is [494,)\left[-\frac{49}{4}, \infty\right).

Would you like more details or have any questions?

Here are 5 related questions:

  1. How do you determine the axis of symmetry for a quadratic function?
  2. Can the range of a quadratic function ever be all real numbers?
  3. How would the range change if the parabola opened downwards?
  4. What is the significance of the discriminant in a quadratic equation?
  5. How do you find the y-intercept of a quadratic function?

Tip: The vertex form of a quadratic equation can be very useful for quickly identifying the vertex and range of the function.

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Math Problem Analysis

Mathematical Concepts

Quadratic Functions
Vertex of a Parabola
Range of Functions

Formulas

Vertex formula: x = -b / (2a)
Quadratic function: y = ax^2 + bx + c

Theorems

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Suitable Grade Level

Grades 9-12