#Proof that uses mean value theorem for integrals

19 messages · Page 1 of 1 (latest)

finite lagoon
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I'm not sure where to begin for this proof. I understand the mean value theorem proof but not sure how to split the functions so it can be applied.

heady vineBOT
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tropic mulch
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It's between min f and max f times int g

finite lagoon
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@tropic mulch i don't understand what you mean

tropic mulch
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What don’t you understand? The notation or the mathematical reasoning? I can write it in Latex if needed but for me it is 3h50 am, I am using a tablet, I won’t switch on my computer now.

finite lagoon
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what's the it's part?

harsh lantern
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f(a) < f(c) < f(b) where a is the value where f(x) is at its minimum and b being the value where f(x) is at its maximum

finite lagoon
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yes I get that part. but how does g(x) get incorporated in?

tropic mulch
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It = the LHS

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m ≤ f(x) ≤ M, multiply by g(x) and integrate

finite lagoon
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Like this?

wild pebble
# finite lagoon

Yes now consider the function h(t)=f(t) * int(g(x)) you know that here h(a)<=int(f(x) *g(x)) <= h(b) with h(a) the minimum and h(b) the maximum now what can you conclude using the intermediate value theorem ?

finite lagoon
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Oh that (1/int g)*int(fg) = f(c)

wild pebble
finite lagoon
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Ah ok thanks for your help @wild pebble @harsh lantern @tropic mulch

upbeat umbraBOT
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@finite lagoon has given 1 rep to @wild pebble @tropic mulch @harsh lantern

finite lagoon
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+close