Question 1182285
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First find the roots of the polynomial from the quadratic equation


        -0.1875x2 + 0.5625x + 0.328125 = 0


    It is EQUIVALENT to

        x^2 - 3x - 1.75 = 0


    The roots are


        {{{x[1,2]}}} = {{{(3 +- sqrt(3^2 + 4*1.75))/2}}} = {{{(3 +- sqrt(16))/2}}} = {{{(3 +- 4)/2}}}.


        {{{x[1]}}} = {{{(3-4)/2}}} = -0.5;   {{{x[2]}}} = {{{(3+4)/2}}} = 3.5.


So, the arch is anchored at  {{{x[1]}}} = -0.5  and  {{{x[2]}}} = 3.5.


The stream is between  x= 0  and  x= 3,

The width of the stream is  3 - 0 = 3 meters.


The arch has maximum height exactly half the way between the roots at x= 1.5.


The height of the arch is the value of the polynomial at x= 1.5


    {{{h[max]}}} = -0.1875*1.5^2 + 0.5625*1.5 + 0.328125 = 0.75 m.
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Solved.