Recent content by hartigan83

Is there a formula? Homework Statement Determine the sum of all the four digit numbers formed by using the digits 1,3,5, and 7. NO DIGIT REPEATED in any number. Homework Equations thats my question... The Attempt at a Solution I can solve this problem by simply writing out all...

Thanks all I figured it out :)

I am not sure how do do it without getting common denomionators and such... so here is my algebra... I know that all of them have absolute value and the lim next to them but I can't figure out how to use them so I will just write the frations. 2^(2n+2) -1 2^(n+1) divided by: 2^(2n)-1...

Homework Statement may be it will help if I included the whole problem, maybe I am not doing it correctly at all. Consider the sequence 1,5/2,21/4,85/8,... defined by s(sub1) =1 , a(sub2)=5/2 and a(subn)= (5/2)a(subn-1) - a(subn-2) A.) Show that a(subn) = (2/3)[2^n -2^(-n)] for any n...

right I see that but I am not sure how to "prove it" I guess I need to show that the limit is infinity but I don't know how.

I thought that the sequence diverged but I have to prove it not just say that it does and I don't know exactally how to show it Thats why I was using the ration test...but I couldn't figure out how to do the limits.

The series sum, sigma notation sorry I just dindt know how to put that on here

simple limit? Homework Statement I am trying to prove if a series is convergent. the series is a(sub n) = (2/3)[2^n - 2^(-n)] from n=1 to infinity. Homework Equations Ratio test: the limit as n approached infinity of the absolute value of a(sub n+1) /a(sub n) equals r. If r is less...

thanks soooooo much! You are right the second way is sooooo much eisier!

Thanks I was confused for a minute thinking that I was supposed to include degree 3 too...

thanks for the encouragement, but I don't feel like I am getting anywhere closer to finding a basis...:frown: so pick another random element such as (4,5,5) and find out how to write it in terms of v(sub1) and v(sub2)? 4 + 5x + 25x^2 =a(1 + 3x +3x^2) + b(0 +1x + 1x^2) Now I see that a=4...

why (x,y,z) where x=y, wouldny it be y=z? and I am not really sure how to find a basis other than picking random elements like I did above...

I am in a problem seminar class and I have not taken Linear Algebra in over 4 years so I am having a lot of problems with this. Please help...:eek: Homework Statement Let P be the set of all polynomials with real coefficients and of degree less than 3. Thus, P = {f:f(x)= a(sub0)...

Ok here is what I have come up with. please tell me if there is a flaw in my reasoning. I have (1+x^2)^n *(1+x^2) {call this equation A} >/= (greater than or eqaul to) (1+2(x^n)+x^(2n)+x^2+2(x^n)*x^2) {call this equation B} I want (1+x^2)^n *(1+x^2) {A} >/= (1 + 2(x^n+1) + x^(2n+2){call...

I am not sure how to use binomial coefficients can you please explain more? I realize that x^n times X gives me x^(n+1) and I have realized that inorder to get the left sides to look the same it is necessary to multiply (1+x^2)^n by (1+x^2) but when I do this, I know that I also have to...