Decimal places for value stored
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Hello, im wondering if there any way i could perform calculation using values up to 4 decimal places only.
For example,i write this in command windows:
x=4.21;
h=0.001;
f=@(x) x^3 + 8*x^2 + 23*x +3;
f2_prime = (f(x+h)-2*f(x)+f(x-h))/(h^2);
how can i make the value of f(x), f(x+h) and f(x-h) to be only up to 4 decimal places when calculating for f2_prime?
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Accepted Answer
Ameer Hamza
on 1 Dec 2020
You can use round()
x=4.21;
h=0.001;
f=@(x) x^3 + 8*x^2 + 23*x +3;
f2_prime = (round(f(x+h),4)-2*f(x)+round(f(x-h),4))/(h^2);
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More Answers (1)
Walter Roberson
on 1 Dec 2020
how can i make the value of f(x), f(x+h) and f(x-h) to be only up to 4 decimal places when calculating for f2_prime?
You would need to use fixed-point arithemetic, such as from the Fixed Point Toolbox.
A close second would be to use the Symbolic Toolbox with digits(4), but it turns out that the Symbolic Toolbox uses "guard digits" ... I think I read once that it uses 5 guard digits -- and the minimum permitted is digits(2)
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