Question

Hi again! I posted a pic 27.bmp of my work...Can someone please check me? It's a radius of convergence problem...The pic is posted. Thanks! :o)

Answer 1

Sorry if I was sloppy...I was writing really fast...lol :o)

Answer 2

the radius does not include an "x"

Answer 3

uh oh...

Answer 4

do you know where I went wrong?

Answer 5

your limit is stuff is fine till the end when you do that <1

Answer 6

\[|\frac{f(x)}{5}|<1\]
\[|f(x)|<5\]

Answer 7

ok...so i should have multiplied both sides by 5...then what?

Answer 8

f(x) = (2x+3)(5x-71); so it has intercepts at x=-3/2 and x=71/5

since it expands to a positive leading coeff; its a parabola that opens up

Answer 9

or should i have foiled (2x+3)(5x-71) earlier and then multiplied by 5?