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Radical Real Value Resolution (Posted on 2023-09-01) Difficulty: 3 of 5
Consider this relationship:
       7√x - 5√x = 3√x - √x
Determine the total number of real values of x that satisfy the abovementioned relationship.

See The Solution Submitted by K Sengupta    
Rating: 5.0000 (1 votes)

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Solution computer solution | Comment 1 of 2
syms x
fplot(@(x)x^(1/7)-x^(1/5)-x^(1/3)+x^(1/2))
grid

low=.001; high=.1;y=1;
while low<high && abs(y)>1e-16
  mid=(low+high)/2;
  x=mid;
  y=x^(1/7)-x^(1/5)-x^(1/3)+x^(1/2);
  if y<0
    high=mid;
  else
    low=mid;
  end
end
x,y

shows that one solution is x=1 and another is very close to zero, and is about x=0.0117154772664753. There is also x=0.

These are the three roots verified by Wolfram Alpha also.

  Posted by Charlie on 2023-09-01 12:03:55
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