- Thu Feb 28, 2013 10:52 pm
- Forum: Calculus
- Topic: Velocity? "A ball is thrown vertically upward..."
- Replies:
**1** - Views:
**1957**

A ball is thrown vertically upward from the top o f a 100-ft-high building. Its height above the ground at time t is given by h(t)=100+30t-16t^2 At what time is the ball falling toward the earth at 46 ft/sec? I've worked this problem several times, yet I always come out with the answer as t=-1/2. Th...

- Tue May 03, 2011 4:09 pm
- Forum: Intermediate Algebra
- Topic: economic formula
- Replies:
**5** - Views:
**4076**

What do you mean by a sales volume equation? Or a revenue equation? I have never heard of either of them. Thanks for your help!

- Thu Apr 28, 2011 5:20 pm
- Forum: Intermediate Algebra
- Topic: economic formula
- Replies:
**5** - Views:
**4076**

Thank you. I understand the canoe example, and that is actually how I began my problem, writing down concrete numbers and translating it to a formula, and figured that, for my problem, my equation was -20p^2+100p+1000. And they only ask for an equation, not an answer, so I figured I did not need to ...

- Thu Apr 28, 2011 4:47 pm
- Forum: Intermediate Algebra
- Topic: economic formula
- Replies:
**5** - Views:
**4076**

I've been given an economics problem in my calculus class. I have an example with a formula, from a previous assignment, but it doesn't seem to apply to my current problem. Suppose that 1000 frankfurters can be sold every week at a food stand for $1 each. For every increase of $.20 per frankfurter, ...

- Wed Mar 23, 2011 6:52 pm
- Forum: Calculus
- Topic: non linear function derivative
- Replies:
**2** - Views:
**2208**

Thank you so much for your help. I derivated with respect to time. So x dx/dt + y dy/dt =0. Solve algebraically and get dx/dt= -ydy/xdt and plug in the given values. The velocity, -3, is dy/dt, and x and y are 4 and 3, respectively. The answer is 9/4.

Thanks again!

Thanks again!

- Fri Mar 18, 2011 7:19 pm
- Forum: Advanced Algebra ("pre-calculus")
- Topic: imaginary numbers? value of (1 + i)^100
- Replies:
**4** - Views:
**2284**

So the answer would be 2^50?

- Fri Mar 18, 2011 7:10 pm
- Forum: Advanced Algebra ("pre-calculus")
- Topic: imaginary numbers? value of (1 + i)^100
- Replies:
**4** - Views:
**2284**

You are right, I wasn't thinking.

- Fri Mar 18, 2011 7:08 pm
- Forum: Calculus
- Topic: non linear function derivative
- Replies:
**2** - Views:
**2208**

A particle moves in a circular orbit described by the equation x^2 +y^2=25. As it passes through (4.3), its y coordinate is decreasing at a rate of 3 units/sec. What is the rate of change of the x coordinate the instant the particle is passing through the point (4,3)? I figured I would dreivate the ...

- Tue Jan 18, 2011 5:44 pm
- Forum: Advanced Algebra ("pre-calculus")
- Topic: imaginary numbers? value of (1 + i)^100
- Replies:
**4** - Views:
**2284**

(1+i)^100 equals which of the following quantities?

(a) 2^100

(b) -2^50

(c) 2^50

(d)1-2^100

I do know that i^2 is -1. so i^100=-1^50, right?

1^100=1.

So, 1-1^50 is what I come up with, and that is 0. Not an option. Can you tell me where I'm going wrong?

(a) 2^100

(b) -2^50

(c) 2^50

(d)1-2^100

I do know that i^2 is -1. so i^100=-1^50, right?

1^100=1.

So, 1-1^50 is what I come up with, and that is 0. Not an option. Can you tell me where I'm going wrong?

- Mon Dec 13, 2010 8:40 pm
- Forum: Calculus
- Topic: Functional notation confusing.
- Replies:
**6** - Views:
**3617**

I'm sorry to be so thick. Can we start over? f(x)=2/x and (f(x+h)-f(x))/h so I sub the second equation into the first, right? And end up with 2h/((x+h)-x), which must not be right... because solved algebraically it does NOT give me the right answer. So I need help with the very first step, I think. ...