## Search found 54 matches

Tue Feb 11, 2014 8:20 am
Forum: Calculus
Topic: The stiffness of a rectangular beam varies as its breadth...
Replies: 2
Views: 2345

### Re: The stiffness of a rectangular beam varies as its breadt

Thank you for putting me on the right track. Solving the derivative of: (144-h^2)^0.5 * h^3 = 0, this gives: 3 h^2(144-h^2)^0.5 - h^4(144-h^2)^-0.5 = 0 (by the poduct rule). Solving this eqn: h = -6*sqrt(3) and h = 6*sqrt(3), (only the positive value is valid). So the height should be 10.4 inches an...
Sun Feb 09, 2014 10:04 am
Forum: Calculus
Topic: The stiffness of a rectangular beam varies as its breadth...
Replies: 2
Views: 2345

### The stiffness of a rectangular beam varies as its breadth...

Hi, can someone help me getting started with this problem?

The stiffness of a rectangular beam varies as its breadth and as the cube of its hight. Find the dimensions of the stiffest beam which can be cut from a circular log 12 inches in diameter.

Thanks.
Luke.
Fri Nov 29, 2013 9:07 am
Topic: Finding the graph of an equation
Replies: 6
Views: 2992

### Re: Finding the graph of an equation

Thanks for your hint and showing me the solution on the Wolfram website.
Part of the implicit plot is shown there.
This plot is what I was after.
How can I get this same plot on my graphic calculator (if this is possible)?
Luke.
Thu Nov 28, 2013 7:50 pm
Topic: Finding the graph of an equation
Replies: 6
Views: 2992

### Re: Finding the graph of an equation

If I could graph this equation, I would be able to see what points (x,y) are on this graph, so then I could derive the slopes of the tangent lines at several of these points. One solution is (2,1) so this surely is one point on the graph and the slope of the tangent line here is -(11/10) (after impl...
Thu Nov 28, 2013 2:57 pm
Topic: Finding the graph of an equation
Replies: 6
Views: 2992

### Finding the graph of an equation

How can I graph the following equation?
x^3 * y^2 = x * y^3 + 6
I don't know how to isolate y (to get y as a function of x).
Thanks.
Luke.
Fri Jun 07, 2013 2:14 pm
Forum: Intermediate Algebra
Topic: Exponential system of eqn's.
Replies: 4
Views: 2765

### Re: Exponential system of eqn's.

OK, the log rules helped me out, I found the solutions now, thanks for your help.

Greetings.

Luke.
Thu Jun 06, 2013 1:53 pm
Forum: Intermediate Algebra
Topic: Exponential system of eqn's.
Replies: 4
Views: 2765

### Re: Exponential system of eqn's.

Sorry, but I still can't solve these eqn's so please help. This is what I have till now: ln (4 * e^(.2/y))= ln e ^(1/y)) => (1.386 * .2)/y ln e = (1/y) ln e ( with ln e = 1) So (1.386 * .2)/y = 1/y . But these are clearly not equal to each other, so I must have done something wrong, but I can't figu...
Tue Jun 04, 2013 5:48 pm
Forum: Intermediate Algebra
Topic: Exponential system of eqn's.
Replies: 4
Views: 2765

### Exponential system of eqn's.

How can I solve this system? (e = natural log)

x * e ^ -(0.2/y) = 4 (1)

x * e ^ -(1/y) = 1 (2)

I know that x= 5.65 and y= .577 but how do I get these values?

From the second eqn. I get:

ln x = 1/y, but how do I solve x = 4 * e ^(.2/y) ?

Thanks.
Tue Sep 18, 2012 7:14 pm
Forum: Intermediate Algebra
Topic: Solving a system of two eqn's.
Replies: 3
Views: 1931

### Solving a system of two eqn's.

How to solve the following system of two equations?
(13/x) - (2/y) = - 0.3
(14.6/x) - (0.4/y) = 0.04
Thanks.
Wed Mar 14, 2012 6:46 pm
Forum: Intermediate Algebra
Topic: solve irrational eqn.: (x-9)^(1/3) - (x+26)^(1/3) + 5 = 0
Replies: 3
Views: 1793

### Re: solve irrational eqn.: (x-9)^(1/3) - (x+26)^(1/3) + 5 =

Hi, I checked the equation and there are no errors, when I solve this eqn. with my graphic calculator (TI89) it gives me two roots 1 and -18, but sadly this thing only gives me the results and not how to get to them. According to my textbook it should be done like you mentioned by cubing both member...