Math Problem Statement

Jawaban soal berikut?

The variables x and y are connected by the equation y = -x^2 + 2x + 1. Some corresponding values of x and y are given in the table. The tasks involve calculating values of p, graphing, and solving related quadratic equation problems.

Solution

Let's work through the problem in the image step by step.

(a) Find the value of pp

The equation given is y=x2+2x+1y = -x^2 + 2x + 1.

We are tasked to find pp, which corresponds to x=0.5x = 0.5 in the table.

Substituting x=0.5x = 0.5 into the equation: y=(0.5)2+2(0.5)+1y = -(0.5)^2 + 2(0.5) + 1 y=0.25+1+1=1.75y = -0.25 + 1 + 1 = 1.75 Thus, p=1.75p = 1.75.

(b) Draw the graph of y=x2+2x+1y = -x^2 + 2x + 1

You are instructed to graph the equation y=x2+2x+1y = -x^2 + 2x + 1 for 1x3-1 \leq x \leq 3.

Here’s how you would plot the points:

xxy=x2+2x+1y = -x^2 + 2x + 1
-1-2
01
0.51.75
12
21
3-2

Plot these points on the grid and draw the curve.

(c) Use the graph in part (b) to find:

(i) The value of yy when x=0.7x = 0.7

From the graph, we can estimate the value of yy when x=0.7x = 0.7, or we can use the equation to calculate it:

y=(0.7)2+2(0.7)+1y = -(0.7)^2 + 2(0.7) + 1 y=0.49+1.4+1=1.91y = -0.49 + 1.4 + 1 = 1.91

So, y1.91y \approx 1.91.

(ii) The values of xx when y=0.5y = 0.5

To find when y=0.5y = 0.5, we substitute y=0.5y = 0.5 into the equation and solve for xx:

0.5=x2+2x+10.5 = -x^2 + 2x + 1 x2+2x+0.5=0-x^2 + 2x + 0.5 = 0 Multiplying by -1 to simplify: x22x0.5=0x^2 - 2x - 0.5 = 0

Using the quadratic formula: x=(2)±(2)24(1)(0.5)2(1)x = \frac{-(-2) \pm \sqrt{(-2)^2 - 4(1)(-0.5)}}{2(1)} x=2±4+22=2±62x = \frac{2 \pm \sqrt{4 + 2}}{2} = \frac{2 \pm \sqrt{6}}{2} x=1±621±1.22x = 1 \pm \frac{\sqrt{6}}{2} \approx 1 \pm 1.22 So, x2.22x \approx 2.22 or x0.22x \approx -0.22.

(iii) The maximum value of yy and the value of xx at which this occurs

The maximum value of yy for a quadratic equation y=x2+2x+1y = -x^2 + 2x + 1 occurs at the vertex, given by:

x=b2ax = \frac{-b}{2a} Here, a=1a = -1 and b=2b = 2, so: x=22(1)=1x = \frac{-2}{2(-1)} = 1

Substituting x=1x = 1 into the equation: y=(1)2+2(1)+1=1+2+1=2y = -(1)^2 + 2(1) + 1 = -1 + 2 + 1 = 2

So, the maximum value of yy is 2, and it occurs at x=1x = 1.

(d) State the equation of the line of symmetry of the graph

The line of symmetry for a parabola is the vertical line through the vertex. From part (c)(iii), the vertex occurs at x=1x = 1.

Thus, the equation of the line of symmetry is: x=1x = 1

Would you like further details or clarifications on any part?

Here are some related questions to expand on the concepts:

  1. What is the general form of a quadratic equation, and how do we find its vertex?
  2. Can you derive the quadratic formula and explain each term?
  3. How does the sign of aa in ax2+bx+cax^2 + bx + c affect the direction of the parabola?
  4. What methods are available for solving quadratic equations besides the quadratic formula?
  5. How do you determine the domain and range of a quadratic function?

Tip: Always check the vertex and axis of symmetry of a quadratic equation to easily sketch the graph and find maximum or minimum values.

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Math Problem Analysis

Mathematical Concepts

Quadratic Functions
Graphing
Parabolas

Formulas

Quadratic equation: y = -x^2 + 2x + 1
Vertex of a quadratic function: x = -b / 2a
Quadratic formula: x = [-b ± sqrt(b^2 - 4ac)] / 2a

Theorems

Quadratic Function Properties
Symmetry of Parabolas
Axis of Symmetry

Suitable Grade Level

Grades 9-12