Recent content by NotaPhysicist

I get it now. Since is the second term in the arithmetic sequence (a- d)+ (a)+ (a+ d)= 3a= 15 a= 3 I thought that would lead to a solution. But I'm still stuck. Too many pages of wasted algebra. I'm giving up on this one. Thanks again for your help.

Yes, this is the same problem, word for word from the text. Unfortunately I can't follow your progress. I can follow up until (a- d)+ (a)+ (a+ d)= 3a= 15 I don't know how you got that. I've fooled around with it a bit, I won't embarrass myself to say exactly how long I've spent trying to...

Sorry to everyone who tried to help. I have now retyped the original question. a + b + c = 15 (successive terms of geometric progression) b, a, c (successive terms of an arithmetic progression)

I'm struggling with latex. I know HTML and can code in C, but for the life of me I need more examples. Can someone point me to a reference that is less than a gazzillion pages long and longer than two pages of reference code. Just something to get me started on my way...

Homework Statement The three number a, b, c, whose sum is 15, are successive terms of an geometric sequence, and b, a and c are successive terms of an arithmetic sequence. Find the values of a, b and c. Edit: I wrote the question wrong. It now reads correctly. I also fixed my latex code...

I got it! Solving for S_4 as above yields a value for r, and from there the other values can be solved, not a quadratic equation in sight. Thank you. I'm a bit slow on the uptake, but I'm beginning to understand how you guys work now. You don't just hand out the fish, you instead teach us how...

I'm still stuck. So I end up with S_3 = 27(1 - r^3) Then where do I go from there? Trying to find the common ratio leaves me with a mess. I know I should end up with a quadratic equation and two sets of solutions, but I completely stumped on how to get there.

For some reason my latex code isn't working. Latex is voodoo magic. No doubt about it.

Homework Statement Find the first three terms of a geometric sequence given that the sum of the first four terms is 65/3 and the sum to infinity is 27. Homework Equations \begin{array}{1} S_n = \frac{a(1 - r^n)}{1 - r}\\ S_n = \frac{a(r^n - 1}{r - 1} \end{array} The Attempt...

I had to read your answer a couple of times. I get it now. Its an infinite sum. No powers to work out. Thank you so much.

The problem had turned out to be the browser. Once I write some latex markup and click "preview", I get my first look at the result. Subsequently if I want to see revisions after clicking "preview" again, I have to refresh the page. Otherwise I see the old markup in the newly reviewed page. It...

I've edited the original post. The problem is to find the value of x. Its not an infinite sum. The only solution I can see is to solve for n in the infinite series and the summation, and try to solve simultaneously.

Homework Statement If 1 + 2x + 4x^2 + ... = \frac{3}{4} find the value of x. [Edit: Forgot to ask the question] Homework Equations S_n = \frac{a(1 - r^n)}{1 - r} t_n = ar^{n-1} The Attempt at a Solution a = 1 r = 2x I try to solve S_n and end up with 2x^n = \frac{6x - 7}{4}...

Thank you for doing that.

Homework Statement I know this is the wrong place. I tired to post in Science materials but it wouldn't let me. Trying to do this in latex t_n = ar^(n-1) t_n=ar^{n-1} Getting weird results. I'm using Chrome on Vista. Its driving me nuts. I'm trying to post questions. Can someone sort me out?