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Evaluate the indefinite integral.
integar x4/1 + x^10 dx

User Ceeroover
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1 Answer

1 vote

Answer:


\int\ {(x^4)/(1 + x^(10))} \, dx = (1)/(5)( \arctan(x^5)) + c

Explanation:

Given


\int\ {(x^4)/(1 + x^(10))} \, dx

Required

Integrate

We have:


\int\ {(x^4)/(1 + x^(10))} \, dx

Let


u = x^5

Differentiate


(du)/(dx) = 5x^4

Make dx the subject


dx = (du)/(5x^4)

So, we have:


\int\ {(x^4)/(1 + x^(10))} \, dx


\int\ {(x^4)/(1 + x^(10))} \, (du)/(5x^4)


(1)/(5) \int\ {(1)/(1 + x^(10))} \, du

Express x^(10) as x^(5*2)


(1)/(5) \int\ {(1)/(1 + x^(5*2))} \, du

Rewrite as:


(1)/(5) \int\ {(1)/(1 + x^(5)^2))} \, du

Recall that:
u = x^5


(1)/(5) \int\ {(1)/(1 + u^2)}} \, du

Integrate


(1)/(5) * \arctan(u) + c

Substitute:
u = x^5


(1)/(5) * \arctan(x^5) + c

Hence:


\int\ {(x^4)/(1 + x^(10))} \, dx = (1)/(5)( \arctan(x^5)) + c

User Rabensky
by
4.0k points