#how to do this?

37 messages · Page 1 of 1 (latest)

spare rose
cursive nightBOT
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spare rose
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can i have other method other then get s2+c2=1
and t^(1/3)/(1+2sc)

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i try u=pi/2-x on it but it doesn't work 😭

zealous zinc
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Set $tan(x)=u^3$

novel hawkBOT
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😑 ɿototoЯ | Rototor 😑

zealous zinc
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(Remember $\frac{1}{cos^2(x)}=1+tan^2(x)$)

novel hawkBOT
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😑 ɿototoЯ | Rototor 😑

zealous zinc
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Then with some integration by parts you can simplify the integral to something easier

fervent flint
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i wonder if theres some sort of reverse quotient rule use here

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i give up integral calculator

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integral calculator also gives up

zealous zinc
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You can also directly integrate by parts but I think it’s easier to do so once the substitution is made

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It basically all comes down to calculating $\int_{0}^{+\infty} \frac{1}{1+u^{3}} du$

novel hawkBOT
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😑 ɿototoЯ | Rototor 😑

zealous zinc
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you need to know which steps to take to get there though I’ll let you see how to using what I told you

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@spare rose

fervent flint
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an idea i tried was to write sinx + cosx as a single function in terms of sin

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and phase shift

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perhaps this could be continued

fervent flint
# spare rose

new idea (NOT MINE) u = x - pi/4 which makes the integral symmetric about 0

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okay but still the cbrt is so annoying 😭

rotund minnow
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we could also use the gamma function

fervent flint
rotund minnow
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yeah you just have to factor out a cos^2 from the denominator and youll see how it goes from there

zealous zinc
# rotund minnow we could also use the gamma function

You can use the gamma function to evaluate $\int_{0}^{+\infty} \frac{1}{1+u^a} du$ for $a>1$ with a simple change of variables you can recognise the beta function, using the relation both functions have you can use Euler’s reflection formula

novel hawkBOT
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😑 ɿototoЯ | Rototor 😑

zealous zinc
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Pretty neat tbh

rotund minnow
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yeah its a nice integral

limpid thicket
spare rose
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thank you guys

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+close

thin matrixBOT
# spare rose +close
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# thin matrix

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