Algebra.Com's Answer #824373 by ikleyn(52787)![\"\"](\"/images/stars/stars-13.gif\")  
You can put this solution on YOUR website!
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document.write( "Find the equation of the tangent to;
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document.write( "f(x) = e^-x at the point where x=2.
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document.write( "So I know dy/dx=-1/e^x, but don't understand how I can sub that x value in the original equation
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document.write( "and find the y value.
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document.write( "You correctly determined the derivative function  = - .\r\n" );
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document.write( "To proceed further, you should substitute x= 2 into the formula. \r\n" );
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document.write( "Doing this way, you will find the value of the derivative at the point x= 2, which is the slope of the function\r\n" );
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document.write( " f(x) =  \r\n" );
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document.write( "at the point x= 2.\r\n" );
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document.write( " So, the slope is m = - .\r\n" );
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document.write( "Now you know the point on the plot of the function: it is ( , ) = ( ,);\r\n" );
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document.write( "and you know the slope: it is m = -.\r\n" );
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document.write( "So, the equation of the tangent line is  =  , or\r\n" );
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document.write( " y - = - .\r\n" );
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document.write( "It is your ANSWER.\r\n" );
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document.write( "You can also use any other EQUIVALENT form of the last equation.\r\n" );
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document.write( "Solved and explained.\r
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document.write( "If you have question/questions, then let me know.\r
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document.write( "If you will post your questions, please refer to the problem's ID number 1192491 .\r
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