Can someone give me a hint for this one ? It's from Elementary Analysis by Ross.
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Originally Posted by kasper90 Can someone give me a hint for this one ? It's from Elementary Analysis by Ross. Look at theorems 33.4 & 33.5. You know that $\displaystyle f(x)\le |f(x)|.$
Okay, I tried it. I thought about this: 1. Let h := |f| - f 2. h is continuous on (a,b) (as |f| and f are) 3. 0 <= h <= 2 |f| (as -f <= |f| ) than use 36.6 ? than integral h exist than integral h - |f| exist (as |f| exist) and integral f exist
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