Math Is Fun Forum

ShivamS

Member

Registered: 2011-02-07

Posts: 3,648

Calculus problem.

Okay, university classes, I have a teacher who thinks that a supposedly "arrogant" student like me should not be allowed to go to university at this age... So she rarely ever teaches me anything, but does give me some hard problems to answer. So for this one, I was a bit confused. Can anyone please help me? Thanks in advance.

A car travels along the path such that the displacement vs. time (meters vs. seconds) graph is given by the equation: x(t)= (6/π)sin-1t•cos-1t. What is the instantaneous velocity of the car at the point (1/2, π/3)?

I am fairly sure that the answer is 2/√3 m/s, but can someone please help me if that isn't the correct answer?

Last edited by ShivamS (2014-03-09 04:17:13)

ShivamS

Member

Registered: 2011-02-07

Posts: 3,648

Re: Calculus problem.

A few more questions by the way.
A strange and unusual particle moves with velocity equal to v(t)=t10•ln(t) m/s. You observe this particle carefully in a lab and find that over the time interval [1, e1/11] the particle moves how many meters?
I believe its 1/121.

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Calculus problem.

Hi Shivamcoder3013;

1)

For the first one, that is what I am getting too.

So she will not teach you anything? Tell her you will not teach her anything either.

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,583

Re: Calculus problem.

hi Shivamcoder3013

Don't know about the university at 12 option.  You might find it a bit lonely with most students being so much older.  You won't even be able to buy your own round of drinks at the bar and what sort of university experience is that? 

But doing hard stuff that you have to solve on your own is a great way to help you develop your brain and it's working isn't it?  Your answer to (1) is correct!

I'm a bit confused about (2).  Did you mean

and

Because, if so, I'm not getting your answer. 

Post back please,

Bob

Last edited by Bob (2011-08-31 19:28:57)

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

anonimnystefy

Real Member

From: Harlan's World

Registered: 2011-05-23

Posts: 16,049

Re: Calculus problem.

hi bob

since his equation has 't10' and not '10t' i think he meant t^10.

---

“Here lies the reader who will never open this book. He is forever dead.
“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment
The knowledge of some things as a function of age is a delta function.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,583

Re: Calculus problem.

hi anonimnystefy

Thanks,  hadn't thought of that. ....... re-computing ............ 

Shivamcoder3013:

So Let's assume the problem is

Arhhh.  That's better. 

Did it 'by parts' and most bits cancel or are zero, leaving

So I agree with answer 2 as well.  Excellent.

:)

Bob

Last edited by Bob (2011-08-31 22:54:53)

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

anonimnystefy

Real Member

From: Harlan's World

Registered: 2011-05-23

Posts: 16,049

Re: Calculus problem.

hi bob

i already did and got:

Last edited by anonimnystefy (2011-08-31 22:42:52)

---

“Here lies the reader who will never open this book. He is forever dead.
“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment
The knowledge of some things as a function of age is a delta function.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,583

Re: Calculus problem.

hi anonimnystefy

Yes, you were right.  Sub in the values and it works out to the OP answer.

Thanks,  that's what I call teamwork!

Bob

Last edited by Bob (2011-08-31 22:55:53)

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

anonimnystefy

Real Member

From: Harlan's World

Registered: 2011-05-23

Posts: 16,049

Re: Calculus problem.

hi bob

i only suggested,but you did most of the work!

also i still haven't got the asnwer.how did you substitute?

Last edited by anonimnystefy (2011-08-31 22:59:43)

---

“Here lies the reader who will never open this book. He is forever dead.
“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment
The knowledge of some things as a function of age is a delta function.

ShivamS

Member

Registered: 2011-02-07

Posts: 3,648

Re: Calculus problem.

Thank you everyone for tyour help.
bob, yes, I have promised myself not to teach her anything either (its surprising how much teachers learn rom the tudents while it should be the contrary).

Bundy, yes it does get fairly lonely I suppose. Although it is fun.

By the way, even though both my answers were right,my idiotic teacher gave me 1/2......

ShivamS

Member

Registered: 2011-02-07

Posts: 3,648

Re: Calculus problem.

Oh and yes, sorry for the typing mistake bob. I just typed everything my teacher told me, and she usually tries to make me fail by giving the question without including exponents.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,583

Re: Calculus problem.

hi Shivamcoder3013

By the way, even though both my answers were right,my idiotic teacher gave me 1/2......

Perhaps the questions were too difficult for her.

Anytime, you want an answer checked, post it here.  And I'm a teacher (I've got certificates and all that) and I give you 100%.

And a smily face! 

Bob

I'd do a gold star but it would take too long.

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

anonimnystefy

Real Member

From: Harlan's World

Registered: 2011-05-23

Posts: 16,049

Re: Calculus problem.

hi bob

why don't you do a gold star once,than copy it,paste it in Notepad,save and use when you need it?

---

“Here lies the reader who will never open this book. He is forever dead.
“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment
The knowledge of some things as a function of age is a delta function.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,583

Re: Calculus problem.

Maybe next time.  And I'd probably save it as a GIF on my website so I can use it as a picture whenever I want.

Bob

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

anonimnystefy

Real Member

From: Harlan's World

Registered: 2011-05-23

Posts: 16,049

Re: Calculus problem.

can you just tell me what your website is?

---

“Here lies the reader who will never open this book. He is forever dead.
“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment
The knowledge of some things as a function of age is a delta function.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,583

Re: Calculus problem.

Here's a clue:

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

anonimnystefy

Real Member

From: Harlan's World

Registered: 2011-05-23

Posts: 16,049

Re: Calculus problem.

can't you just tell me?

---

“Here lies the reader who will never open this book. He is forever dead.
“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment
The knowledge of some things as a function of age is a delta function.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,583

Re: Calculus problem.

Yes but it's a challenge.  I use my webspace mostly for my students.  When you solve the challenge you will understand why I don't want to post it here too obviously.

Think about it and you'll figure out how to go there.

Bob

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

anonimnystefy

Real Member

From: Harlan's World

Registered: 2011-05-23

Posts: 16,049

Re: Calculus problem.

a little more help?

---

“Here lies the reader who will never open this book. He is forever dead.
“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment
The knowledge of some things as a function of age is a delta function.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,583

Re: Calculus problem.

#14

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

ShivamS

Member

Registered: 2011-02-07

Posts: 3,648

Re: Calculus problem.

bob, perhaps. Or the fact that she despises me severely, similar to most of my other teachers (although I am very rule-abiding).

Bob

Administrator

Registered: 2010-06-20

Posts: 10,583

Re: Calculus problem.

hi Shivamcoder3013

To think they despise you may be paranoia on your part, but let's assume it's true.

Some teachers find it difficult to deal with a student who is more intelligent than they are.  They find it threatening because it turns their world up-side-down.  Try not to be cross with them because of it.  Rather, pity them for their lack of intelligence and inability to cope with someone who is more clever.

For me, it is not a problem.  I don't mind admitting it when I learn something from a student; I tell them I don't know about that and get them to explain it to me.  As it boosts their confidence I can always pretend I'm doing this for their benefit.

One ICT student was shocked to discover I didn't know which 'f' button to press to switch graphics onto a second screen.  Then his 'Mac' went wrong and I fixed it even though I've never used one in my life.  His faith was restored.

On this site you will find there are regulars who give help to others.  Sometimes we have to help each other.  So we are used to explaining and to having something explained. 

btw: see post #16 for your gold star!

Bob

Last edited by Bob (2011-09-01 00:09:24)

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

anonimnystefy

Real Member

From: Harlan's World

Registered: 2011-05-23

Posts: 16,049

Re: Calculus problem.

hi bob

do you have any students on this forum?

---

“Here lies the reader who will never open this book. He is forever dead.
“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment
The knowledge of some things as a function of age is a delta function.

ShivamS

Member

Registered: 2011-02-07

Posts: 3,648

Re: Calculus problem.

Well, I wouldn't state exactly that I am smarter than my teacher. Jacob Barnett maybe, but surely not me. But it may be true, and if it is, it would be even worse for me. As my teacher has a huge superiority complex.

ShivamS

Member

Registered: 2011-02-07

Posts: 3,648

Re: Calculus problem.

Oh and thanks for the gold star, it would be impossible for me to make that (I am horrible at art).