The basic quadratic functionย y=x2 with the addition of C yields the functionย y=x2+c The meaning of C is the vertical shift of the function upwards or downwards. If C is positive: the function will rise by the number of steps shown in C. If C is negative: the function will descend by the number of steps shown in C.ย
Additionally, we can see thatC marks the intersection point on the Y axis.
Examples and exercises with solutions from the family of parabolas y=xยฒ+c
Exercise #1
One function
y=โ2x2โ3
to the corresponding graph:
Video Solution
Step-by-Step Solution
To solve this problem, we'll match the given function y=โ2x2โ3 with its corresponding graph based on specific characteristics:
The function y=โ2x2โ3 is a quadratic equation representing a parabola.
Since the coefficient of x2 is negative, the parabola opens downward.
The y-intercept is -3, which means the parabola crosses the y-axis at โ3.
The maximum point (vertex) of the parabola occurs at its axis of symmetry, from which we know it opens downward from that point.
Given these observations, we analyze each graphical option:
Graph 1 represents a parabola opening upward, so it does not match.
Graph 2 might have an appropriate direction but not the correct intercept.
Graph 3 doesn't match key features such as y-intercept and direction.
Graph 4 shows a downward opening parabola with its intercept significantly influenced by negative vertical shift, which matches y=โ2x2โ3.
Therefore, the function y=โ2x2โ3 matches with graph option 4.
Answer
4
Exercise #2
One function
y=โ6x2
to the corresponding graph:
Video Solution
Step-by-Step Solution
To solve this problem, we need to match the function y=โ6x2 with its graph. This function represents a downward-opening parabola with the vertex at the origin (0,0). The coefficient โ6 is negative, confirming it opens downwards, and its large absolute value indicates that the parabola closes towards the axis more sharply than a standard y=โx2 curve.
Let's identify the characteristics of y=โ6x2:
- The graph is a parabola, opening downwards.
- The vertex is at the origin, (0,0).
- Symmetric around the y-axis.
- Its steepness is greater than the standard parabola y=โx2 due to the coefficient โ6.
By analyzing the given graph options, the graph marked as 4 aligns perfectly with these properties: It is centered on the origin, opens downwards, and has an evident steep slope.
Therefore, the correct graph that matches the function y=โ6x2 is option 4.
Answer
4
Exercise #3
Which chart represents the function y=x2โ9?
Video Solution
Step-by-Step Solution
To solve the problem of identifying which chart represents the function y=x2โ9, let's analyze the function and its graph:
The function y=x2โ9 is a parabola that can be described by the general form y=x2+k where k=โ9.
It is a standard upward-opening parabola with its vertex located at the point (0,โ9). This is because there is no coefficient affecting x, so horizontally it is centered at the origin.
To find the correct graph, we look for one where the bottommost point of the parabola is at (0,โ9). This point, known as the vertex, should sit on the y-axis and be the lowest point of the curve due to the upward opening.
After inspecting the charts:
Chart 4 depicts a parabola opening upwards, with its vertex at (0,โ9). This aligns perfectly with the form and properties of our function y=x2โ9.
Therefore, the chart that represents the function y=x2โ9 is Choice 4.
Answer
4
Exercise #4
One function
y=6x2
to the corresponding graph:
Video Solution
Step-by-Step Solution
The function given is y=6x2. This is a quadratic function, a type of parabola with vertex at the origin (0,0), because there are no additional terms indicating a horizontal or vertical shift.
First, note the coefficient of x2 is 6. A positive coefficient indicates that the parabola opens upwards. The value of 6 means the parabola is relatively narrow, as it is stretched vertically compared to the standard y=x2.
To identify the corresponding graph:
Recognize that a function of the form y=ax2 with a>1 indicates a narrower parabola.
Out of the given graphs, we should look for an upward-opening narrow parabola.
Upon examining each graph, you find that option 2 shows a parabola that is narrower than the standard parabola y=x2 and opens upwards distinctly, matching our function y=6x2.
Therefore, the correct graph for the function y=6x2 is option 2.
Answer
2
Exercise #5
Find the ascending area of the function
f(x)=2x2
Video Solution
Step-by-Step Solution
To determine the intervals where the function f(x)=2x2 is increasing, we will analyze the derivative of the function:
Step 1: Differentiate the function.
The derivative of f(x)=2x2 is fโฒ(x)=4x.
Step 2: Determine where fโฒ(x)>0.
To find the increasing intervals, set 4x>0. Solving this inequality, we obtain x>0.
Therefore, the function f(x)=2x2 is increasing for x>0.
Consequently, the correct answer is the interval where the function is increasing, which is 0<x.
Answer
0<x
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Test your knowledge
Question 1
One function
\( y=-6x^2 \)
to the corresponding graph:
Incorrect
Correct Answer:
4
Question 2
Which chart represents the function \( y=x^2-9 \)?