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???
07/07/05 06:40
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#96752 - square root by newtons method
Responding to: ???'s previous message
Newtons method for finding the square root of a positive number can be summerised as simply calculating the iterative formula


x(n)=1/2(x(n-1)+b/x(n-1))

just keep pluging the new value of x(n) into the formula until it converges.
so to find the square root of 45
by calculator we know the square root of 45 is 6.7082
we make an initial quess lets say 4
x(1) then becomes 7.625
plugging 7.625 into the equation we get
x(2)=6.7633
x(3)=6.7084
x(4)=6.7082
the easiest way to know when the answer has converged is when the difference between sucessive values is less than some value.
the question of how long newtons method takes to converge for a given value leads to chaos theory.


List of 10 messages in thread
TopicAuthorDate
Phase voltage to Line voltage            01/01/70 00:00      
   why is it difficult?            01/01/70 00:00      
   cos(60)            01/01/70 00:00      
      square root            01/01/70 00:00      
   try the code library            01/01/70 00:00      
      Hello Jez            01/01/70 00:00      
   square root by newtons method            01/01/70 00:00      
      Inital guess = B/2            01/01/70 00:00      
   Pell's method            01/01/70 00:00      
      calculating square roots            01/01/70 00:00      

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