Can Two Discontinuous Functions Sum to a Continuous Function?

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Two discontinuous functions can indeed sum to a continuous function, as illustrated by the example of f(x) and g(x). Here, f(x) is defined as 0 for all x except 0, where it equals 1, while g(x) is 0 for all x except 0, where it equals -1. The sum of these functions, f(x) + g(x), results in a function that is continuous everywhere. This demonstrates that the sum can eliminate the discontinuities present in the individual functions. Understanding these concepts is crucial in exploring the behavior of discontinuous functions in mathematics.
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can you give me an example of two discontinuous functions at a number a whose sum is not discontinuous at a? :confused: thanks!:shy:
 
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i was just about to ask a question about dis. functions, and express each function as a composition, and i don't know how to do that??

if you give me a prob, i might help to see what you mean.
 
huh?

If the functions are discontinuous at a, then their sums are not going to be continuous at a. I suppose you could have two step functions, one going up and one going down, but I don't think that is really fair because there is still a discontinunity at a... Mathematicians?
 
Let f(x)=0 when x is not zero, and 1 when x is zero.
Let g(x)=0 when x is not zero, and -1 when x is zero.

then f+g is continuous everywhere.
 
I tried to combine those 2 formulas but it didn't work. I tried using another case where there are 2 red balls and 2 blue balls only so when combining the formula I got ##\frac{(4-1)!}{2!2!}=\frac{3}{2}## which does not make sense. Is there any formula to calculate cyclic permutation of identical objects or I have to do it by listing all the possibilities? Thanks
Since ##px^9+q## is the factor, then ##x^9=\frac{-q}{p}## will be one of the roots. Let ##f(x)=27x^{18}+bx^9+70##, then: $$27\left(\frac{-q}{p}\right)^2+b\left(\frac{-q}{p}\right)+70=0$$ $$b=27 \frac{q}{p}+70 \frac{p}{q}$$ $$b=\frac{27q^2+70p^2}{pq}$$ From this expression, it looks like there is no greatest value of ##b## because increasing the value of ##p## and ##q## will also increase the value of ##b##. How to find the greatest value of ##b##? Thanks
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