« previous next »
Pages: [1]   Go Down

Author Topic: Pure Maths help (Trig Integrals)  (Read 1443 times)

Offline Priya

  • Newbie
  • *
  • Posts: 39
  • Reputation: 20
Pure Maths help (Trig Integrals)
« on: May 27, 2009, 06:44:42 pm »
Could you tell me what is the integral of sec x... Is it sec x+tan x +c or sec x*tan x
Is using secxtanx in this video http://www.youtube.com/watch?v=8CHHY-2Ctug&feature=related @ 2.25 appropriate?

Pls reply...
Thanks for helping me out!
« Last Edit: May 27, 2009, 07:27:27 pm by Priya »
Logged

Offline astarmathsandphysics

  • SF Overlord
  • *********
  • Posts: 11271
  • Reputation: 65534
  • Gender: Male
  • Free the exam papers!
Re: Pure Maths help (Trig Integrals)
« Reply #1 on: May 27, 2009, 07:18:43 pm »
It is ln(secx+tanx)
Logged

Offline Priya

  • Newbie
  • *
  • Posts: 39
  • Reputation: 20
Re: Pure Maths help (Trig Integrals)
« Reply #2 on: May 27, 2009, 07:36:01 pm »
Thank you!

And I was confusing integration with differentiation in that video. Understood it now... Thanks again!!
Logged

Offline astarmathsandphysics

  • SF Overlord
  • *********
  • Posts: 11271
  • Reputation: 65534
  • Gender: Male
  • Free the exam papers!
Re: Pure Maths help (Trig Integrals)
« Reply #3 on: May 27, 2009, 07:38:34 pm »
Multiply tanx by (tanx+secx)/(secx+tanx) and expand the brackets. Top is derivative of bottom so substittu u=(tanx+secx) to get du/u then integrate
Logged
Pages: [1]   Go Up
« previous next »