Write the equation of the axis of symmetry, and find the coordinates of the

vertex of the graph of each function. Identify the vertex as a maximum or

minimum. Then graph the function.

y = - x ^2 + 2x + 3

Write the equation of the axis of symmetry, and find the coordinates of the

vertex of the graph of each function. Identify the vertex as a maximum or

minimum. Then graph the function.

y = - x ^2 + 2x + 3

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^{2 }+ bx + c , if a > 0 vertex is a minimum of quadratic function (or the lowest point on a parabola),

if a < 0 vertex is a maximum of quadratic function (or the highest point on a parabola).

The x-coordinate of a vertex is x = -b/2a , and that will be an equation of the axis of symmetry. y-coordinate of the vertex is the maximum or minimum value of the function.

~~~~~~~~~~~~~~~~

y = -x^{2 }+ 2x + 3 , a = -1, b = 2, c = 3. the x-coordinate of a vertex is x = -2/2(-1) = 1

To find the y-coordinate of the vertex or the maximum value of function need to substitute "x" by 1 in given equation y = (-1)·1^{2
}+ 2·1 + 3 = 4 .

**(1,4) - coordinates of vertex, x = 1 is equation of the axis of symmetry, y = 4 is the max of function.**

Now, to build the graph we have to find the roots of equation -x^{2 }+ 2x + 3 = 0 ,

x_{1,2 }= (-b ± √(b^{2} - 4ac))/2a x_{1,2} = (-2 ± √(2^{2} -4·(-2)·3)/(2·(-1)) , x_{1} = (-2 + √28)/(-2) ~ (-1.65)

x_{2} = (-2 - √28)/(-2) ~ 3.65

Plot the coordinates of vertex, coordinate of y-intercept (0,3) then on x-axis mark the coordinates: -1.65 and 3.65 . Start drawing the left branch of parabola: down from vertex through (0,3) and -1.65 , after that right branch: down from vertex through 3.65.

P.S. You may begin to graph the function by making a table of values for some values of your function and then plot those values in a coordinate plane and draw a smooth curve through the points.

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