document.write( "Question 1160419: A baseball diamond is a square with sides of length 90 ft. A batter hits the ball and runs toward first base with a speed of 22 ft/s. \r
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Algebra.Com's Answer #783800 by math_helper(2461) $\"\"$ $\"About$

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document.write( "This is a related-rates problem.\r
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document.write( "The distance h from the runner to 2nd base is 
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document.write( "where x is the remaining distance from the runner to 1st base.\r
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document.write( "Given:
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document.write( " but note that because the way I've defined x, it is decreasing.  Therefore I will write  so if we get a negative answer it indicates a decreasing distance. \r
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document.write( "[ If you instead insist on dx/dt > 0, you can say dx/dt=22 ft/s and define x as the distance from home plate to the runner, then the distance remaining to first base is 90-x and you end up with the minus sign later, but the math is a little uglier. ]\r
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document.write( "Using the chain rule:
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document.write( " = \r
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document.write( "Plugging in x=45 gives   ft/s
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document.write( " (The runner's distance with respect to 2nd base is decreasing at 9.839 ft/s)\r
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