Remove A Factor Of $\sec^2 X$ From The Integrand:$\int \sec^6 X \tan^{10} X \, Dx = \int (\sec^4(x) \tan^{10}(x)) \sec^2 X \, Dx$---Rewrite In Terms Of $\tan X$:$\sec^4 X \tan^{10} X = (1 + \tan^2(x))^2

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Introduction

In calculus, we often encounter integrals that involve trigonometric functions, particularly the secant and tangent functions. When dealing with integrals of the form secmxtannxdx\int \sec^m x \tan^n x \, dx, we may need to remove a factor of sec2x\sec^2 x from the integrand to simplify the integral. In this article, we will explore how to remove a factor of sec2x\sec^2 x from the integrand and rewrite the integral in terms of tanx\tan x.

Removing a Factor of sec2x\sec^2 x from the Integrand

To remove a factor of sec2x\sec^2 x from the integrand, we can use the following substitution:

sec6xtan10xdx=(sec4(x)tan10(x))sec2xdx\int \sec^6 x \tan^{10} x \, dx = \int (\sec^4(x) \tan^{10}(x)) \sec^2 x \, dx

This substitution allows us to rewrite the integral as a product of two integrals, one of which is a power of secx\sec x and the other is a power of tanx\tan x. We can then use the following identity to simplify the integral:

sec4xtan10x=(1+tan2(x))2\sec^4 x \tan^{10} x = (1 + \tan^2(x))^2

This identity allows us to rewrite the integral in terms of tanx\tan x.

Rewriting in Terms of tanx\tan x

To rewrite the integral in terms of tanx\tan x, we can use the following substitution:

u=tanxu = \tan x

This substitution allows us to rewrite the integral as:

(1+u2)2u10du\int (1 + u^2)^2 u^{10} \, du

We can then use the following identity to simplify the integral:

(1+u2)2=1+2u2+u4(1 + u^2)^2 = 1 + 2u^2 + u^4

This identity allows us to rewrite the integral as:

(1+2u2+u4)u10du\int (1 + 2u^2 + u^4) u^{10} \, du

We can then use the following power rule of integration to simplify the integral:

undu=un+1n+1+C\int u^n \, du = \frac{u^{n+1}}{n+1} + C

This power rule allows us to rewrite the integral as:

(1+2u2+u4)u10du=u1111+2u1313+u1515+C\int (1 + 2u^2 + u^4) u^{10} \, du = \frac{u^{11}}{11} + \frac{2u^{13}}{13} + \frac{u^{15}}{15} + C

We can then substitute back u=tanxu = \tan x to obtain the final result:

sec6xtan10xdx=tan11x11+2tan13x13+tan15x15+C\int \sec^6 x \tan^{10} x \, dx = \frac{\tan^{11} x}{11} + \frac{2\tan^{13} x}{13} + \frac{\tan^{15} x}{15} + C

Conclusion

In this article, we have shown how to remove a factor of sec2x\sec^2 x from the integrand and rewrite the integral in terms of tanx\tan x. We have used the following substitution to simplify the integral:

sec6xtan10xdx=(sec4(x)tan10(x))sec2xdx\int \sec^6 x \tan^{10} x \, dx = \int (\sec^4(x) \tan^{10}(x)) \sec^2 x \, dx

We have then used the following identity to rewrite the integral in terms of tanx\tan x:

sec4xtan10x=(1+tan2(x))2\sec^4 x \tan^{10} x = (1 + \tan^2(x))^2

We have also used the following power rule of integration to simplify the integral:

undu=un+1n+1+C\int u^n \, du = \frac{u^{n+1}}{n+1} + C

This power rule has allowed us to rewrite the integral as:

(1+2u2+u4)u10du=u1111+2u1313+u1515+C\int (1 + 2u^2 + u^4) u^{10} \, du = \frac{u^{11}}{11} + \frac{2u^{13}}{13} + \frac{u^{15}}{15} + C

We have then substituted back u=tanxu = \tan x to obtain the final result:

sec6xtan10xdx=tan11x11+2tan13x13+tan15x15+C\int \sec^6 x \tan^{10} x \, dx = \frac{\tan^{11} x}{11} + \frac{2\tan^{13} x}{13} + \frac{\tan^{15} x}{15} + C

References

  • [1] Calculus, 3rd edition, Michael Spivak
  • [2] Calculus, 2nd edition, James Stewart
  • [3] Trigonometry, 2nd edition, Charles P. McKeague

Discussion

This article has shown how to remove a factor of sec2x\sec^2 x from the integrand and rewrite the integral in terms of tanx\tan x. The substitution used in this article is a common technique used in calculus to simplify integrals. The power rule of integration used in this article is also a common technique used in calculus to simplify integrals.

The final result obtained in this article is a common result in calculus, and it can be used to solve a variety of problems involving integrals of trigonometric functions.

Related Articles

  • [1] Integration by Substitution: This article discusses how to use substitution to simplify integrals.
  • [2] Integration by Parts: This article discusses how to use integration by parts to simplify integrals.
  • [3] Trigonometric Integrals: This article discusses how to simplify integrals involving trigonometric functions.

Comments

Introduction

In our previous article, we discussed how to remove a factor of sec2x\sec^2 x from the integrand and rewrite the integral in terms of tanx\tan x. In this article, we will answer some common questions that readers may have about this topic.

Q: What is the purpose of removing a factor of sec2x\sec^2 x from the integrand?

A: The purpose of removing a factor of sec2x\sec^2 x from the integrand is to simplify the integral and make it easier to evaluate. By removing this factor, we can rewrite the integral in terms of tanx\tan x, which can be easier to work with.

Q: How do I know when to remove a factor of sec2x\sec^2 x from the integrand?

A: You should remove a factor of sec2x\sec^2 x from the integrand when you see a power of secx\sec x multiplied by a power of tanx\tan x. This is because the identity sec4xtan10x=(1+tan2(x))2\sec^4 x \tan^{10} x = (1 + \tan^2(x))^2 allows us to rewrite the integral in terms of tanx\tan x.

Q: What is the substitution used to remove a factor of sec2x\sec^2 x from the integrand?

A: The substitution used to remove a factor of sec2x\sec^2 x from the integrand is:

sec6xtan10xdx=(sec4(x)tan10(x))sec2xdx\int \sec^6 x \tan^{10} x \, dx = \int (\sec^4(x) \tan^{10}(x)) \sec^2 x \, dx

This substitution allows us to rewrite the integral as a product of two integrals, one of which is a power of secx\sec x and the other is a power of tanx\tan x.

Q: How do I evaluate the integral after removing a factor of sec2x\sec^2 x from the integrand?

A: After removing a factor of sec2x\sec^2 x from the integrand, you can use the power rule of integration to evaluate the integral. The power rule of integration states that:

undu=un+1n+1+C\int u^n \, du = \frac{u^{n+1}}{n+1} + C

You can use this rule to evaluate the integral after removing a factor of sec2x\sec^2 x from the integrand.

Q: What are some common mistakes to avoid when removing a factor of sec2x\sec^2 x from the integrand?

A: Some common mistakes to avoid when removing a factor of sec2x\sec^2 x from the integrand include:

  • Not recognizing the identity sec4xtan10x=(1+tan2(x))2\sec^4 x \tan^{10} x = (1 + \tan^2(x))^2 and not using it to rewrite the integral in terms of tanx\tan x.
  • Not using the power rule of integration to evaluate the integral after removing a factor of sec2x\sec^2 x from the integrand.
  • Not checking the work and making sure that the integral is evaluated correctly.

Q: How can I practice removing a factor of sec2x\sec^2 x from the integrand?

A: You can practice removing a factor of sec2x\sec^2 x from the integrand by working through examples and exercises. You can also try removing a factor of sec2x\sec^2 x from the integrand in different types of integrals, such as integrals of the form secmxtannxdx\int \sec^m x \tan^n x \, dx.

Conclusion

In this article, we have answered some common questions that readers may have about removing a factor of sec2x\sec^2 x from the integrand and rewriting the integral in terms of tanx\tan x. We hope that this article has been helpful in clarifying any confusion and providing additional practice and examples.

References

  • [1] Calculus, 3rd edition, Michael Spivak
  • [2] Calculus, 2nd edition, James Stewart
  • [3] Trigonometry, 2nd edition, Charles P. McKeague

Discussion

This article has provided additional practice and examples for removing a factor of sec2x\sec^2 x from the integrand and rewriting the integral in terms of tanx\tan x. The questions and answers in this article have covered a range of topics, from the purpose of removing a factor of sec2x\sec^2 x from the integrand to common mistakes to avoid.

Related Articles

  • [1] Integration by Substitution: This article discusses how to use substitution to simplify integrals.
  • [2] Integration by Parts: This article discusses how to use integration by parts to simplify integrals.
  • [3] Trigonometric Integrals: This article discusses how to simplify integrals involving trigonometric functions.

Comments

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