document.write( "Question 1114527: A ball was kicked into the air from a balcony 20 feet above the ground, and the ball's height above the ground in feet t seconds after the ball was kicked is h(t) = 20 - 16t2 + 32t. What was the maximum height, in feet, of the ball above the ground after it was kicked?\r
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Algebra.Com's Answer #729461 by ikleyn(52800) $\"\"$ $\"About$

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document.write( "The height of the ball over the ground is described by a quadratic function\r\n" );
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document.write( "h(t) = - 16*t^2 + 32t + 20.    (1)\r\n" );
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document.write( "The maximum height is achieved when the quadratic function (1) has the maximum.\r\n" );
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document.write( "From algebra, the quadratic function  y = ax^2 + bx + x has extremum at x = .\r\n" );
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document.write( "In your case,  a= -16,  b= 32,  so  x=  = 1.\r\n" );
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document.write( "Thus the quadratic function (1) achieved maximum at t = 1. It means that the ball will achieve the maximum height at t= 1 seconds.\r\n" );
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document.write( "And the maximum height will be h(1) = -16*1^2 + 32*1 + 20 = 36 ft.\r\n" );
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document.write( "Answer.  The ball will achieve its maximum height of 36 ft in 1 second.\r\n" );
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\n" ); document.write( "On finding the maximum/minimum of a quadratic function see the lessons in this site\r
\n" ); document.write( "\n" ); document.write( "    - HOW TO complete the square to find the minimum/maximum of a quadratic function\r
\n" ); document.write( "\n" ); document.write( "    - Briefly on finding the minimum/maximum of a quadratic function\r
\n" ); document.write( "\n" ); document.write( "    - HOW TO complete the square to find the vertex of a parabola\r
\n" ); document.write( "\n" ); document.write( "    - Briefly on finding the vertex of a parabola\r
\n" ); document.write( "\n" ); document.write( "    - OVERVIEW of lessons on finding the maximum/minimum of a quadratic function\r
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\n" ); document.write( "\n" ); document.write( "Also, you have this free of charge online textbook in ALGEBRA-I in this site\r
\n" ); document.write( "\n" ); document.write( "    - ALGEBRA-I - YOUR ONLINE TEXTBOOK.\r
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\n" ); document.write( "\n" ); document.write( "The referred lessons are the part of this textbook under the topic \"Finding minimum/maximum of quadratic functions\". \r
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\n" ); document.write( "\n" ); document.write( "Save the link to this online textbook together with its description\r
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\n" ); document.write( "\n" ); document.write( "Free of charge online textbook in ALGEBRA-I
\n" ); document.write( "https://www.algebra.com/algebra/homework/quadratic/lessons/ALGEBRA-I-YOUR-ONLINE-TEXTBOOK.lesson\r
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\n" ); document.write( "\n" ); document.write( "to your archive and use it when it is needed.\r
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