Homework Help Forum: Algebra

Posted by Laurie on Sunday, August 2, 2009 at 4:06pm.

A contagious disease is infecting residents of a town of 7,300 residents. The number of residents infected t days after the disease has begun is given by the function f(t)=(7300)/1+500e^-0.5 t How many residents are infected with the disease after 6 days?

• Algebra - MathMate, Sunday, August 2, 2009 at 4:42pm

  When you transcribe formulae involving fractions written in full to a single line, please do not forget that numerators and denominators have implicit parentheses around them. As an example, instead of writing 7300/1+t, it should be written as 7300/(1+t). I suspect the same applies to the above equation. I interpret it as f(t):=7300/(1+500*e^(-0.5)*t) If you follow the correct priority of operations (using your original equation), you should arrive at f(6) = 281.92 = 282 persons. The order of operations calls for calculating -0.5t first, then do the exponentiation in the denominator, multiply by 500 and add to 1. Finally, divide 7300 by the resulting number in the denominator. Remember, a badly transcribed formula gives equally bad results.

  
  

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