# Why cant I use u substitution for equations like 1/(x^3+x)? It seems like u-substitution would do the job.?

• Why cant I use u substitution for equations like 1/(x^3+x)? It seems like u-substitution would do the job.?

u-substitution: u-substitution ... Another example of using u-subsitutionu-substitution example 2where is the course that expains d/dx ... = 1/x , or can ...
Positive: 24 %
... it seems like the best way to do this one would be ... We can now use the substitution and we might ... Not all trig substitutions will ...
Positive: 21 %

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PETERSON’S MASTER AP CALCULUS AB & BC 2nd Edition W. Michael Kelley Mark Wilding, Contributing Author
Positive: 24 %
... (e^6x)cot(e^6x)dx I am calling 'u' my substitution variable. I feel like I ... 1 to 3. I understand how and why I need to do ... x + 1/y + 2/z = 4 2/x ...
Positive: 19 %
Evalute the integral of x/(x^2+4)dx using u-substitution ... (x^3 + 5x^2 + 18 , substitution u ... 1/z = 1 1/x + 1/y + 1/z = 4 2)Solve the system of ...