rockiee
Badges: 2
Rep:
?
#1
Report Thread starter 13 years ago
#1
Hi, I've got a quick question:

What is the derivative of sec^2(x) [sec squared x] :confused:

Thanks!
0
reply
joe8232
Badges: 0
Rep:
?
#2
Report 13 years ago
#2
Using the product rule you differentiate the outside which is 2secx and then times the differential of secx which is secxtanx so the answer is 2sec^2xtanx.
0
reply
CossLne
Badges: 15
Rep:
?
#3
Report 13 years ago
#3
(Original post by rockiee)
Hi, I've got a quick question:

What is the derivative of sec^2(x) [sec squared x] :confused:

Thanks!
Think u have to use the chain rule.

y=u^2 u=secx
dy/du =2u du/dx=tanxsecx
dy/dx= dy/du x du/dx (dy/du multiplied by du/dx)
dy/dx = 2u times tanxsecx substitute u=secx

dy/dx= 2secx tanxsecx = 2tanxsec^2x
Hope thats right.
0
reply
cdpuk
Badges: 0
Rep:
?
#4
Report 13 years ago
#4
Beat me to it, but I've added it as example 4 here:

http://wikinotes.cdpuk.net/wiki/The_chain_rule

with a little more explanation

-Chris
0
reply
joe8232
Badges: 0
Rep:
?
#5
Report 13 years ago
#5
Doh! I meant the chain rule
0
reply
gyrase
Badges: 0
Rep:
?
#6
Report 13 years ago
#6
(Original post by rockiee)
Hi, I've got a quick question:

What is the derivative of sec^2(x) [sec squared x] :confused:

Thanks!
For some reason I feel you meant the integral of sec^2(x) ?

If so, its quite hard to do, and you would just differentiate tanx to show its the integral of sec^2(x)
0
reply
rockiee
Badges: 2
Rep:
?
#7
Report Thread starter 13 years ago
#7
Thanks everyone! I also managed to get the answer through using the trig identity of sec^2(x) i.e. 1+tan^2(x) and I got the same answer as above.

Thanks for all your help!
0
reply
X

Quick Reply

Attached files
Write a reply...
Reply
new posts
Back
to top
Latest
My Feed

See more of what you like on
The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

Personalise

University open days

  • The University of Law
    Solicitor Series: Assessing Trainee Skills – LPC, GDL and MA Law - Guildford campus Postgraduate
    Wed, 29 Jan '20
  • Nottingham Trent University
    Postgraduate Open Day Postgraduate
    Wed, 29 Jan '20
  • University of Groningen
    Undergraduate Open Day Undergraduate
    Fri, 31 Jan '20

Have you ever signed up for an open day and then not gone to it?

Yes (188)
52.51%
No (170)
47.49%

Watched Threads

View All