Question

I think I have the right answers but I don't know how to do the sigma.
My answers are:
1) 3
2) 588
3) 1288
4) 10.64705882

http://www.mathbits.com/caching/PC4782976.html

Answer 1

i think 1 is wrong, remember its an absolute value function

sum from -2 to 3 = 3+2+1+0+1+2 = 9

Answer 2

#2 = 352 not 588

Answer 3

#3 = 484

Answer 4

#4 = 11

Answer 5

What does it mean at the bottom, like what do I plug in for n

Answer 6

the answers to each problem

= (#1^2 +1) + (#2^2 +1) +(#3^2 +1) +(#4^2 +1)

Answer 7

how did you come up with your answers?

do you know the formulas for arithmetic and geometric sequences

Answer 8

oh, alright thanks! do you by chance know how to do these? I have been working on them but I think they are wrong. And yes, that's what I used, so I don' know why I was so off.

Answer 9

Arithmetic:

An = A1 +d(n-1)
Sn = (n/2)(A1 +An)

Geometric:

An = A1*r^(n-1)
Sn = A1(r^n -1)/(r-1)

Answer 10

Yeah, that is what I used...I don't know what I did. Do these make sense?
http://mathbits.com/Caching/PC7503125.html

Answer 11

yeah

First to plot complex numbers, think of the real part as x-axis and imaginary part as y-axis

i^2 = -1

to rationalize a denominator, multiply top and bottom by conjugate
conjugate to (a+bi) is (a-bi)
when you do this the i's cancel out on the bottom

Answer 12

so it would be 4?

Answer 13

For those answers I got:
1) 1
2) a=-2
b=1
3)25
4) 4

Answer 14

#1 would be quadrant 4
x-positive, y-negative

Answer 15

I said 4? Oh I typoed when I typed them all out, I said 4 earlier.

Answer 16

for #2, how did get a=-2,b=1

\[\frac{(-2+3i)(1-3i)}{(1+3i)(1-3i)}\]

Answer 17

So it would be a=7 and b=9?

Answer 18

almost, now you are on the right track
however the denominator is 10 so think of it as splitting it into 2 fractions

a = 7/10, b= 9/10

Answer 19

oh got it! thanks! are the others right because i cant seem to get the URL