Additivity Integration Problem

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Homework Statement



View attachment latex-image-1.pdf equals...

Homework Equations



\int_a^{b} f(x)dx+\int_b^{c} f(x)dx=\int_a^{c} f(x)dx

\int_b^{a} f(x)dx=-\int_a^{b} f(x)dx

The Attempt at a Solution



View attachment latex-image-1.pdf

View attachment latex-image-2.pdf

\int_2^{-1} f(x)dx-\int_2^{5} f(x)dx

\int_2^{-1} f(x)dx+\int_5^{2} f(x)dx

\int_5^{-1} f(x)dx

The answer key says the answer is View attachment latex-image-3.pdf Where did i go wrong?
 
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rrrright said:

Homework Statement



View attachment 30603 equals...

Homework Equations



\int_a^{b} f(x)dx+\int_b^{c} f(x)dx=\int_a^{c} f(x)dx

\int_b^{a} f(x)dx=-\int_a^{b} f(x)dx

The Attempt at a Solution



View attachment 30603

View attachment 30604

\int_2^{-1} f(x)dx-\int_2^{5} f(x)dx

\int_2^{-1} f(x)dx+\int_5^{2} f(x)dx

\int_5^{-1} f(x)dx

The answer key says the answer is View attachment 30605 Where did i go wrong?

I get
-\int_{-1}^{5} f(x)dx
which is the same as what you got. It looks to me like the answer key is missing the - sign out front.
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
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