Efficiently Solve ∫tan^3(x) dx Using tan^2(x)+1=sec^2(x) in 3 Steps

  • Thread starter Thread starter november1992
  • Start date Start date
  • Tags Tags
    Integral
Click For Summary
SUMMARY

The integral ∫tan^3(x) dx can be efficiently solved using the identity tan^2(x) + 1 = sec^2(x). The solution involves rewriting tan^3(x) as tan^2(x) * tan(x), leading to the integral ∫(sec^2(x) - 1) tan(x) dx. The final result is expressed as (tan^2(x)/2) - sec^2(x) + C, where C is the constant of integration. This method streamlines the calculation and clarifies the relationship between the tangent and secant functions.

PREREQUISITES
  • Understanding of integral calculus
  • Familiarity with trigonometric identities
  • Knowledge of the properties of secant and tangent functions
  • Ability to perform integration by substitution
NEXT STEPS
  • Study integration techniques involving trigonometric functions
  • Learn about integration by parts and its applications
  • Explore advanced trigonometric identities and their proofs
  • Practice solving integrals involving secant and tangent functions
USEFUL FOR

Students studying calculus, particularly those focusing on integration techniques, as well as educators seeking effective methods to teach trigonometric integrals.

november1992
Messages
120
Reaction score
0

Homework Statement



∫[itex]tan^{3}[/itex]x dx

Homework Equations



[itex]tan^{2}x[/itex]+1 = [itex]sec^{2}[/itex]x

[itex]tan^{3}[/itex]x = [itex]tan^{2}[/itex]x * tan(x)

The Attempt at a Solution



∫[itex]tan^{2}[/itex]x * tan(x) dx

∫([itex]sec^{2}[/itex]x -1 ) tan(x) dx

∫([itex]sec^{2}[/itex]xtan(x) -∫tan(x)

∫u du - [itex]sec^{2}[/itex]x

[itex]u^{2}[/itex]/2 - [itex]sec^{2}[/itex]x

[itex]tan^{2}[/itex]x/2 - [itex]sec^{2}[/itex]x
 
Physics news on Phys.org
Oh damn. I just realized integral of tanx is ln|secx|.

I got it wrong on my test :(
 

Similar threads

  • · Replies 5 ·
Replies
5
Views
3K
  • · Replies 8 ·
Replies
8
Views
2K
Replies
2
Views
2K
Replies
3
Views
2K
  • · Replies 15 ·
Replies
15
Views
2K
  • · Replies 5 ·
Replies
5
Views
1K
  • · Replies 10 ·
Replies
10
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 3 ·
Replies
3
Views
2K