# Finding the second derivative of (arcosh(x))^2Watch

#1
This problem has stumped me for hours now, and I'm getting rather frustrated with it!

This is what I'm getting:

That's using the product rule. I get something different with the quotient rule.

What's worse is that my textbook's answer of,

doesn't agree with the horrendous thing WolframAlpha throws up: http://www.wolframalpha.com/input/?i...28Arccosh%29^2

Last edited by StandardCarpet; 8 years ago
0
quote
8 years ago
#2
(Original post by StandardCarpet)
This problem has stumped me for hours now, and I'm getting rather frustrated with it!

This is what I'm getting:

That's using the product rule. I get something different with the quotient rule.

What's worse is that my textbook's answer of,

doesn't agree with the horrendous thing WolframAlpha throws up: http://www.wolframalpha.com/input/?i...28Arccosh%29^2

I get:

by product and quotient rules.
quote
#3
(Original post by ghostwalker)
I get:

by product and quotient rules.
That tallys with Wolfram's derivation for x=2, so I'm gonna assume my textbook's just been misprinted without the first bit.

Would it be much to ask your working from the first to second derivation? I'd really appreciate it.
0
quote
8 years ago
#4
(Original post by StandardCarpet)
That tallys with Wolfram's derivation for x=2, so I'm gonna assume my textbook's just been misprinted without the first bit.

Would it be much to ask your working from the first to second derivation? I'd really appreciate it.
Quotient or product rule? State your preferance (I won't do both).
quote
#5
(Original post by ghostwalker)
Quotient or product rule? State your preferance (I won't do both).
Product rule would be awesome. Thanks.
0
quote
8 years ago
#6
(Original post by StandardCarpet)
...
so, starting from:

we have

Or to put it more neatly.

Last edited by ghostwalker; 8 years ago
quote
8 years ago
#7
Note: just spotted the power of the denominator of that second fraction should be positive not negative.
0
quote
8 years ago
#8
(Original post by Tla)
Note: just spotted the power of the denominator of that second fraction should be positive not negative.
Yep, I was in the middle of correcting it, and corrected the wrong one, thus having to correct it again. Ho, hum!
quote
8 years ago
#9
(Original post by ghostwalker)
Yep, I was in the middle of correcting it, and corrected the wrong one, thus having to correct it again. Ho, hum!
0
quote
#10
(Original post by ghostwalker)
so, starting from:

we have

Or to put it more neatly.

Thank you so much!!!!
0
quote
X

new posts
Latest
My Feed

### Oops, nobody has postedin the last few hours.

Why not re-start the conversation?

see more

### See more of what you like onThe Student Room

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

### University open days

• Sheffield Hallam University
Wed, 17 Oct '18
• Staffordshire University
Wed, 17 Oct '18
• Teesside University
Wed, 17 Oct '18

### Poll

Join the discussion

#### Who is most responsible for your success at university

Mostly me (238)
91.54%
Mostly my university including my lecturers/tutors (22)
8.46%