# Differential equationsWatch

#1

In part (i) I can verify that h satisfies the equation by substituting the value of dh/dt:

0.2 = 0.1 (9 - h)^(1/3)

2 = (9-h)^(1/3)

8 = 9 - h

h = 1

But how can I verify t ?

Also a hint for part (ii) will be appreciated.
0
9 years ago
#2
I think for part (i) you already showed them that because proves both since t is a function of h

hint for part (ii) :=====> Chainrule
0
#3
(Original post by darkness9999)
I think for part (i) you already showed them that because proves both since t is a function of h
Ok thanks.

hint for part (ii) :=====> Chainrule
I have tried this but the answer is wrong:

dh/dt x dt/dh = 0.1 (9 - h)^(1/3)

0.2 x dt/dh = 0.1 (9 - h)^(1/3)

dt/dh = 0.1/0.2 x (9-h)^(1/3)
dt/dh = 0.5 x (9 - h)^(1/3)

Integrating both sides

What have I done wrong?
0
9 years ago
#4
Just re-arrange the differential equation. This gives:

Unparseable or potentially dangerous latex formula. Error 4: no dvi output from LaTeX. It is likely that your formula contains syntax errors or worse.
{(9-h)^{-\frac{1}{3}} \, dh = 0.1 dt

Then integrate!

EDIT: Sorry about the difficulties I was having with the LaTeX there... It's all fixed now!
0
#5
(Original post by Mathematician!)
Just re-arrange the differential equation. This gives:

Then integrate!

EDIT: Sorry about the difficulties I was having with the LaTeX there... It's all fixed now!
Thanks a lot, I am getting the correct answer now.
0
9 years ago
#6
(Original post by Hashmi)
Thanks a lot, I am getting the correct answer now.
No problem.

EDIT: And thanks for the rep!
0
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

• Cranfield University
Cranfield Forensic MSc Programme Open Day Postgraduate
Thu, 25 Apr '19
• University of the Arts London
Open day: MA Footwear and MA Fashion Artefact Postgraduate
Thu, 25 Apr '19
• Cardiff Metropolitan University
Sat, 27 Apr '19

### Poll

Join the discussion

#### Have you registered to vote?

Yes! (490)
37.72%
No - but I will (100)
7.7%
No - I don't want to (88)
6.77%
No - I can't vote (<18, not in UK, etc) (621)
47.81%