Math Problems

Think you're good at math? Here's a very simple problem.
What is the radius of this circle? . . .

Think you're good at math? Here's a very simple problem.
What is the radius of this circle? . . .

r-2 or r-x take your pick

r-2 or r-x take your pick

I am looking for a precise numerical value.
But... if r is referring to the radius, why subtract 2 or x? Why wouldn't it just be r?

Quote from: cbarnett97 on January 19, 2009, 05:30:25 PM

r-2 or r-x take your pick

I am looking for a precise numerical value.
But... if r is referring to the radius, why subtract 2 or x? Why wouldn't it just be r?

I set the radius as R you should have known that by how clear I made the difference between the r's 

Ah, so you could have simply responded with R.

Ah, so you could have simply responded with R.

Yes
I may work on it for real in a bit.

Clever...the "x" and "2" are really just red herrings.  I was trying to figure out how I would use "sin" or whatever.  God I hate math.

But everyone loves trig   Well, identities at least.  Too bad those things are worth almost nothing of trig units, because they're like little games giving you a break half way through the test.

Three men get a hotel room. The man up front says it is 30 dollars. They all pay ten dollars and head upstairs. Suddenly the owner realizes it is saturday, and the cost of the room is only 25 dollars. He sends the bellhop up to pay them back, but the bellhop knows they can't evenly divide 5 dollars among 3 people so he keeps two himself and returns the 3 dollars to the men. Which means they each pay 9 dollars. and the bellhop kept two. Meaning they paid 29 dollars. What happened to the other dollar?

Quote from: Raist on January 19, 2009, 06:29:09 PM

Three men get a hotel room. The man up front says it is 30 dollars. They all pay ten dollars and head upstairs. Suddenly the owner realizes it is saturday, and the cost of the room is only 25 dollars. He sends the bellhop up to pay them back, but the bellhop knows they can't evenly divide 5 dollars among 3 people so he keeps two himself and returns the 3 dollars to the men. Which means they each pay 9 dollars. and the bellhop kept two. Meaning they paid 29 dollars. What happened to the other dollar?

3 x 9 = 27 = 25 + 2

The man up front has it.

No, the man up front has 25.

(25+2)/3= 9 , 9 + 1 = 10, 10 x 3 = 30

This is how I understood to be answered.  I'm not sure if I did it right but I'm pretty sure it boils down to improper order of PEMDAS.

The way it's put and the way I work it through in my head don't agree.  I don't find a missing dollar, but putting it in terms of each paying $9 + bell boy it doesn't work out.

(25+2)/3= 9 , 9 + 1 = 10, 10 x 3 = 30

This is how I understood to be answered.  I'm not sure if I did it right but I'm pretty sure it boils down to improper order of PEMDAS.

That is what it is

What is two plus two divided by two

What is two plus two divided by two

3

A little derivative problem.

A sphere is expanding at 3pi, at what rate is the sphere expanding when the radius is 3?

Quote from: cbarnett97 on January 19, 2009, 06:41:53 PM

What is two plus two divided by two

3

put it in a scientific calculator exactly as it reads

Quote from: Wakka Wakka on January 19, 2009, 06:50:11 PM

A little derivative problem.

A sphere is expanding at 3pi, at what rate is the sphere expanding when the radius is 3?

your retarted.

Meany, its from my calculus book.

A little derivative problem.

A sphere is expanding at 3pi, at what rate is the sphere expanding when the radius is 3?

Uh you dropped some info.

Quote from: Wakka Wakka on January 19, 2009, 06:50:11 PM

A little derivative problem.

A sphere is expanding at 3pi, at what rate is the sphere expanding when the radius is 3?

Uh you dropped some info.

Fine i'll go find the full problem.

Air is being pumped into a spherical balloon at a rate of 3 cm3/min.  Determine the rate at which the radius of the balloon is increasing when the diameter of the balloon is 12 cm.

(for simplicity, say the balloon is a perfect sphere)

Quote from: Mr. Ireland on January 19, 2009, 06:45:42 PM

Quote from: cbarnett97 on January 19, 2009, 06:41:53 PM

What is two plus two divided by two

3

put it in a scientific calculator exactly as it reads

Yea, 2+2/2 = 3.

Air is being pumped into a spherical balloon at a rate of 3 cm3/min.  Determine the rate at which the radius of the balloon is increasing when the diameter of the balloon is 12 cm.

(for simplicity, say the balloon is a perfect sphere)

0.0144?  I may have done it incorrectly.

Three men get a hotel room. The man up front says it is 30 dollars. They all pay ten dollars and head upstairs. Suddenly the owner realizes it is saturday, and the cost of the room is only 25 dollars. He sends the bellhop up to pay them back, but the bellhop knows they can't evenly divide 5 dollars among 3 people so he keeps two himself and returns the 3 dollars to the men. Which means they each pay 9 dollars. and the bellhop kept two. Meaning they paid 29 dollars. What happened to the other dollar?

Actually, each man paid $8.33 (25/3).  Each man got back a dollar and the bellhop has two.  So there is only one penny missing.

Quote from: Raist on January 19, 2009, 06:29:09 PM

Three men get a hotel room. The man up front says it is 30 dollars. They all pay ten dollars and head upstairs. Suddenly the owner realizes it is saturday, and the cost of the room is only 25 dollars. He sends the bellhop up to pay them back, but the bellhop knows they can't evenly divide 5 dollars among 3 people so he keeps two himself and returns the 3 dollars to the men. Which means they each pay 9 dollars. and the bellhop kept two. Meaning they paid 29 dollars. What happened to the other dollar?

Actually, each man paid $8.33 (25/3).  Each man got back a dollar and the bellhop has two.  So there is only one penny missing.

But you used insufficient significant figures. Dollars are units, and an exact value has been established with pennies. You could have used infinite significant figures.

Quote from: markjo on January 19, 2009, 07:41:13 PM

Quote from: Raist on January 19, 2009, 06:29:09 PM

Three men get a hotel room. The man up front says it is 30 dollars. They all pay ten dollars and head upstairs. Suddenly the owner realizes it is saturday, and the cost of the room is only 25 dollars. He sends the bellhop up to pay them back, but the bellhop knows they can't evenly divide 5 dollars among 3 people so he keeps two himself and returns the 3 dollars to the men. Which means they each pay 9 dollars. and the bellhop kept two. Meaning they paid 29 dollars. What happened to the other dollar?

Actually, each man paid $8.33 (25/3).  Each man got back a dollar and the bellhop has two.  So there is only one penny missing.

But you used insufficient significant figures. Dollars are units, and an exact value has been established with pennies. You could have used infinite significant figures.

So you do have change for a penny?

Quote from: Raist on January 19, 2009, 07:45:37 PM

Quote from: markjo on January 19, 2009, 07:41:13 PM

Quote from: Raist on January 19, 2009, 06:29:09 PM

Three men get a hotel room. The man up front says it is 30 dollars. They all pay ten dollars and head upstairs. Suddenly the owner realizes it is saturday, and the cost of the room is only 25 dollars. He sends the bellhop up to pay them back, but the bellhop knows they can't evenly divide 5 dollars among 3 people so he keeps two himself and returns the 3 dollars to the men. Which means they each pay 9 dollars. and the bellhop kept two. Meaning they paid 29 dollars. What happened to the other dollar?

Actually, each man paid $8.33 (25/3).  Each man got back a dollar and the bellhop has two.  So there is only one penny missing.

But you used insufficient significant figures. Dollars are units, and an exact value has been established with pennies. You could have used infinite significant figures.

So you do have change for a penny?

No, but I can have a mental representation of part of a penny owed to me by a friend. We would go straight to the gas station, and divide a tootsie rule between ourselves to repay the debt.

Quote from: cbarnett97 on January 19, 2009, 06:50:42 PM

Quote from: Mr. Ireland on January 19, 2009, 06:45:42 PM

Quote from: cbarnett97 on January 19, 2009, 06:41:53 PM

What is two plus two divided by two

3

put it in a scientific calculator exactly as it reads

Yea, 2+2/2 = 3.

That is not what I said take your scientific calculator a type it just like this 2 + 2 / 2 =
You wrote this: the sum of 2+2 divided by 2

now an easy one:
Does this series diverge or converge
1/n^p

Edit: From one to infinity

Doesn't it depend on whether p is >1 or </= 1?

Doesn't it depend on whether p is >1 or </= 1?

Yeah I wanted to see if anyone caught it, so lets go with p<1

Extra credit for the name of the test that determines this and what other test it is an offshoot of