Are You Ready to Challenge Your Integral Solving Skills?

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  • Thread starter Thread starter Gib Z
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    Integrals
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Discussion Overview

The thread revolves around participants sharing and solving indefinite integrals, with varying levels of difficulty. The discussion includes requests for integrals, attempts at solving them, and exchanges of hints and strategies for integration techniques.

Discussion Character

  • Homework-related
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant requests a variety of indefinite integrals to assess their skills and learn from the community.
  • Another participant suggests starting with the integral of sqrt(tan(x)).
  • A different integral involving sin(x) is proposed, leading to expressions of confusion from some participants.
  • Several participants express difficulty with the proposed integrals and seek guidance on substitution methods.
  • Hints are provided, including suggestions for substitutions like u = tan(x) and changes of bounds to simplify integrals.
  • Participants discuss the use of integration by parts and hyperbolic substitutions, with varying levels of understanding and confidence.
  • There are corrections and clarifications regarding differentiation and integration techniques, highlighting misunderstandings among participants.
  • Some participants express frustration or confusion over the complexity of the integrals and the solutions provided.

Areas of Agreement / Disagreement

There is no clear consensus on the best approach to solving the integrals, with multiple competing views and methods suggested. Participants express varying levels of understanding and confidence, leading to a mix of agreement and confusion.

Contextual Notes

Participants demonstrate uncertainty regarding the application of integration techniques and the correctness of their approaches. Some mathematical steps remain unresolved, and there are dependencies on specific substitutions that may not be universally understood.

  • #271
Gib Z said:
Was that aimed at me or rocophysics? I know I stink :( Whats a wine?
It was aimed at you, I've already spoiled :p
 
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  • #272
How good are YOU ?

Here are some of my favourite integrals, ranging from beginners to just no.
Some of these have been posted before, most have not. Have fun.

Have fun and gl

Easier problems at the top, harder problems at the bottom. I really love all of these

Easy

I \, = \, \int {\frac{x}{e^x}} dx
I \, = \, \int_0^{\frac{\pi }{3n}} \tan \left( {nx} \right) dx
I \, = \, \int \frac{x^2+1}{x(x^2+3)} dx
I \, = \, 1+\int_{229}^{1234} (\sin(x)+\cos(x))^2+(\cos(x)-\sin(x))^2 \, dx
I \, = \, \int {\frac{1}{x\ln x}} dx
I \, = \, \int {\frac{{{e^x} + 1}}{{{e^x} - 1}}} dx
I \, = \, \int \frac{\sin(x)}{\sin(x)-1} dx
I \, = \, \int {2^{\ln(x)}} dx
I \, = \, \int {{e^{x + {e^x}}}} dx
I \, = \, \int_0^4 {\frac{\ln \left( x \right)}{\sqrt x}} dx
I \, = \, \int {{e^{\sqrt x }}} dx
I \, = \, \int \frac{1}{x^7-x} dx
I \, = \, \int\limits_0^4 {\frac{1}{{1 + \sqrt x }}} dx
I \, = \, \int \frac{\cos \left( x \right) - \sin \left( x \right)}{\sin \left( x \right) + \cos \left( x \right)} \, dx
I \, = \, \int \frac{\sin(x)\cos(x)}{\cos(x)^4-\sin(x)^4} \, dx
I \, = \, \int \frac{\sqrt{\sqrt{\ln(x)}+1}}{x} dx
I \, = \, \int \frac{1}{1+\sin\left( \frac{\pi}{6} \right)^x} dx
I \, = \, \int {\frac{1}{x \ln{{\left( x \right)}^n}}} dx
I \, = \, \int {\frac{{x{e^x}}}{{{{\left( {x + 1} \right)}^2}}}} dx
I \, = \, \int \frac{2010}{x(1+x^{2010})} dx

Find the area between the function f(x) and the x-axis when f(x)=\sqrt{a-\sqrt{x}}

Show that \int \left( {x + 3} \right) \left( {x - 1} \right)^5 dx \: equals \: \frac{1}{21}\left( {3x + 11} \right){{\left( {x - 1} \right)}^6} + C

Medium

I \, = \, \int \sin(\ln(x)) + \cos(\ln(x)) dx
I \, = \, \int {\left( {1 + 2{x^2}} \right){e^{{x^2}}}} \, dx
I \, = \, \int \frac{\ln(x)-1}{\ln(x)^2} \, dx
I \, = \, \int_{\pi}^{3\pi} \sin(x)\ln(x) - \frac{\cos(x)}{x} \, dx
I \, = \, \int \frac{1}{\ln(x)}+\ln(\ln(x)) \, dx
I \, = \, \int (x+3) \sqrt{e^x \cdot x} dx
I \, = \, \int \arccos(x) + \arcsin(x) dx
I \, = \, \int \frac{1}{\cos(x)} dx
I \, = \, \int \frac{4(\ln x)^2+1}{(\ln x)^{\frac 32}}\ dx
I \, = \, \int \frac{1}{\sqrt[3]{x}+x}\, dx
I \, = \, \int \frac{\sin(x)+\sin(3x)}{\cos(3x)+\cos(x)} \, dx
I \, = \, \int \frac{1}{\sqrt{x+x\sqrt{x}}} \, dx
I \, = \, \int \sin(101x)\cdot\sin(99x) \, dx
I \, = \, \int {\frac{{\sqrt {x + 1} - \sqrt {x - 1} }}{{\sqrt {x + 1} + \sqrt {x - 1} }}} \, dx
I \, = \, \int_0^1 \frac{x}{1+x}\sqrt{1-x^2}\ dx
I \, = \, \int \frac{1}{x^{a+1}+x} \, dx \; a>0
I \, = \, \int \frac{2^x \cdot 3^x}{9^x- 4^x} \, dx
I \, = \, \int \frac{1 + 2x^2}{x^5 \left( 1 + x^2 \right)^3} \, dx
I \, = \, \int \frac{1}{\sqrt{5x+3}-\sqrt{5x-2}} \, dx
I \, = \, \int \frac{\sqrt{x+\sqrt{x^2+1}}}{\sqrt{x^2+1}}
I \, = \, \int_1^e \frac{\ln x-1}{x^2-(\ln x)^2}dx
I \, = \, \int_{1}^{\sqrt{3}} x^{2x^2+1}+\ln(x^{2x^{2x^2+1}}) dx

The integral \; \int\limits_{\frac{\pi }{6}}^{\frac{\pi }{2}} {\sin {{\left( {2x} \right)}^3}\cos {{\left( {3x} \right)}^2} \, dx }
can be written as \; \left( \frac{a}{b} \right)^b where a and b are integers. Find \sqrt{a^b+b^a+1}

I \, = \, \int \frac{\left( x + 2 \right)^5}{\left( x + 7 \right)^2} \, dx
I \, = \, \int \frac{\sinh(x)+\cosh(x)}{\cosh(x)-\sinh(x)} \, dx
I \, = \, \int\limits_0^{\pi /2} {\sqrt {1 - 2\sin \left( {2x} \right) + 3\cos {{\left( x \right)}^2}} dx}
I \, = \, \int_{0}^{\pi/2} \ln(sec(x))
I \, = \, \int_{0}^{a} \frac{1}{\sqrt{x^2+a^2}} dx
I \, = \, \int \sqrt{ \sqrt{x+2\sqrt{2x+4}} + \sqrt{x-2\sqrt{2x+4}} } dx
I \, = \, \int \frac{ \left( 1 + x^2 \right) } { \left( 1 - x^2 \right) \sqrt{1 + x^4} } \, dx
I \, = \, \int \frac{ \sin(x) + \cos(x) }{e^x + 3 \cos(x) } \, dx
I \, = \, \int \sqrt{ \frac{k + x}{x} } \, dx
I \, = \, \int_{0}^{\infty} x^n \cdot e^{-x} \, dx
I \, = \, \int {\frac{x}{1+\cos(x)}} \, dx
I \, = \, \int {\frac{{{x^2} + 1}}{{{x^4} + 1}}} \, dx
I \, = \, \int\limits_{ - \pi }^\pi {\sqrt {1 + \cos \left( x \right)} } \, dx
I \, = \, \int e^{x/2} \cdot \left( \frac{2 - \sin \left( x \right) }{1 - \cos \left( x\right) } \right) \, dx
I \, = \, \int_{0}^{\infty} \frac{\{1-(x-1)e^x\}\ln(x)}{(1+e^x)^2} dx
I \, = \, \int\limits_0^{\ln \left( 2 \right)} {\sqrt {\frac{{{e^x} + 1}}{{{e^x} - 1}}} } \, dx
I \, = \, \int_{0}^{\infty} \frac{1}{ \left( x + \sqrt{1+x^2} \right)^{\phi}} \, dx \qquad \phi=\frac{1+\sqrt{5}}{2}
I \, = \, \int_0^{\infty} \frac{1}{(x^2+2)^3} \, dx
I \, = \, \int \sqrt{\frac{1}{\,\sin(x)+1}\,}\, dx
I \, = \, \int {\sqrt[3] {\tan \left( x \right)} } \, dx
I \, = \, \int_{0}^{\infty} \frac{x^{29}}{(5x^2+49)^{17}}\, dx \, = \, \frac{14!}{2 \cdot 5^{15} \cdot 49^2 \cdot 16! }\, dx
I \, = \, \int \left( \frac{\arctan(x)}{x-\arctan(x)} \right)^2 \, dx

"Fun"

I \, = \, \int_{1}^{\infty} \ln\left( \sqrt[X]{x} \right)^{2011} dx
I \, = \, \int_{0}^{2\pi} \frac{x \sin(x)}{1+\sin(x)^2} dx
I \, = \, \int_{0}^{2\pi} {\frac{1}{1+e^{\cos(x)}}} dx
I \, = \, \int_0^{\frac {\pi}{2}} \frac{(\sin x)^{\cos x}}{(\cos x)^{\sin x} + (\sin x)^{\cos x}} dx
I \, = \, \int_2^{4} \frac{\sqrt{\ln(9-x)}}{\sqrt{\ln(3+x)}+\sqrt{\ln(9-x)}} dx
I \, = \, \int_{-1}^{1} \arctan(e^x) dx
I \, = \, \int_{0}^{1} \ln(x)\cdot\ln(1-x) dx
I \, = \, \int_{-\pi/2}^{\pi/2} \frac{1}{1+2009^x} \cdot \frac{\sin(2010x)}{\sin(2010x)+\cos(2010x)} dx
I \, = \, \int \frac{1}{(x^2+1)^k} dx
I \, = \, \int_{0}^{\infty} \frac{x}{e^x-1} dx
I \, = \, \int_{0}^{a} \frac{1}{x+\sqrt{a^2-x^2}} dx \quad a>0
I \, = \, \int_{0}^{\infty} \frac{\ln{2x}}{x^2+9} dx
I \, = \, \int_{0}^{\pi/2} \ln(1-a \cos(x)) \, dx
I \, = \, \int_{-\infty}^{\infty} \sin(x^2)+\cos(x^2) dx
I \, = \, \int_{-\infty}^{\infty} \frac{x^a+x^b}{\ln(x)} dx \qquad (a,b)\forall >-1
I \, = \, \int_0^1 \frac{\ln(1+x^2)}{1+x^2} dx
I \, = \, \int_{0}^{\infty}\frac{1}{x^n+1} dx \quad n>1
I \, = \, \int_{0}^{\pi} \frac{1-\cos{(n\cdot x)}}{1-\cos(x)} dx \quad n\in\mathbb{N^+}
I \, = \, \int_{0}^{1} \ln(x) \cdot e^{-x} \cdot (1-x) dx
I \, = \, \int_{0}^{\infty} \ln\left( \frac{e^x+1}{e^x-1}\right) dx
I \, = \, \int_{0}^{\pi} \ln \left( 1 - 2\alpha \cos(x) + \alpha^2 \right) dx
I \, = \, \int_0^{\infty} \ln (1+e^{-ax} ) dx \quad a>0
I \, = \, \int_0^{\infty} 1 - x\sin\left( \frac{1}{x} \right) dx
I \, = \, \int_0^{\infty} \ln (1+e^{-ax} ) dx \quad a>0
I = \int_{0}^{\infty} \frac{{{e^{ - x}}\left( {1 - {e^{ - 6x}}} \right)}}{{x\left( {1 + {e^{ - 2x}} + {e^{ - 4x}} + {e^{ - 6x}} + {e^{ - 8x}}} \right)}}dx
I = \int\limits_0^1 {\frac{{\sin \left( {p\ln x} \right) \cdot \cos \left( {q\ln x} \right)}}{{\ln x}}}dx
I \, = \, \int_{a}^{\infty} \frac{1}{x^{n+1} \cdot \sqrt{x^2-a^2}} \, dx n \in \mathbb{N}^{+} \; , \; a>0
I \, = \, \int_{a}^{\infty} \frac{x^{-p}}{1+x} \, dx
I \, = \, \int_{ - \infty }^{\infty} \frac{x\sin x}{1 + x^2}dx
I \, = \, \int_0^{\infty} \sin(x)\cdot\arctan\left( \frac{1}{x} \right) dx
I \, = \, \int_{0 }^{\infty} \frac{1}{x} \cdot \sin(\tan(x)) \, dx

Have fun and gl.
 
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