Question

Evaluate the summation of 25 times 0.3 to the n plus 1 power, from n equals 2 to 10..

Answer 1

does anyone know this.. help

Answer 2

So, you can write this question as \[\sum_{n=2}^{10}25*0.3^n*0.3=\sum_{n=2}^{10}7.5*0.3^n\]

Answer 3

We can write that as \[7.5*0.3^2+7.5*0.3^3+...+7.5*0.3^10\], right?

Answer 4

Correction: The last term is supposed to be 7.5*0.3^10

Answer 5

no this is not right

Answer 6

Why not?

Answer 7

Evaluate the summation of negative 2 n minus 3, from n equals 2 to 10. then how do u do this in sigma notation

Answer 8

\[\sum_{n=2}^{10}(-2n-3)\]

Answer 9

yes!!!!!! thankyou how do you solve this

Answer 10

There is a sigma property.

Answer 11

\[\sum_{x=a}^{b}(nx+m)=n \sum_{x=a}^{b}x+\sum_{x=a}^{b}m\]

Answer 12

a,b,n,m are all constants

Answer 13

okay how do u solve the one i gave you... my answer choices are
-270
-135
135
270

Answer 14

You mea the second one?

Answer 15

yes that one

Answer 16

First, use the sigma property I gave you to get this

Answer 17

\[-2\sum_{n=2}^{10}n-\sum_{n=2}^{10}3\]

Answer 18

can you show me please

Answer 19

On what part do you need help on?

Answer 20

i got 135 but i dont think its right

Answer 21

First, do you know how to calculate \[\sum_{n=2}^{10}n\]

Answer 22

no i really dont. i just learned this

Answer 23

Ok.

Answer 24

If you expand that, you get 2+3+4+5+6+7+8+9+10

Answer 25

okay i got that idk what to do afterwards

Answer 26

2+3+4+5+6+7+8+9+10=A
10+9+8+7+6+5+4+3+2=A


12+12+12+12+12+12+12+12+12=2A
12*9=2A
54=A

Answer 27

So, \[\sum_{n=2}^{10}n=54\]

Answer 28

im confussed bc thats not the answer to my problem :(

Answer 29

Going back to what I previously said, we said that \[\sum_{n=2}^{10}(-2n-3)=-2\sum_{n=2}^{10}n-\sum_{n=2}^{10}3\]

Answer 30

We found that \[\sum_{n=2}^{10}n=54\]

Answer 31

Evaluate the summation of 3 n plus 2, from n equals 1 to 14..

39

49

340

343

Answer 32

So, the 1st equation becomes \[-2(54)-\sum_{n=2}^{10}3=-108-\sum_{n=2}^{10}3\]

Answer 33

\[\sum_{n=2}^{10}3=3*9=27\]

Answer 34

So, the 2nd equation becomes -108-27, which is -135

Answer 35

So,\[\sum_{n=2}^{10}(-2n-3)=-135\]

Answer 36

okay i got that !!!!!

Answer 37

Evaluate the summation of 3 n plus 2, from n equals 1 to 14. how you do this one

Answer 38

Try it on your own.
I'll help if you're stuck.
You can show work on here.

Answer 39

okay so do i do the 1+2+3+4 thing

Answer 40

im not good at this

Answer 41

After that problem, I'll tell you a shortcut to these kind of problems.

Answer 42

okay thankyou. im sorry to give you all this trouble

Answer 43

so do i do the 1+2+3 thing

Answer 44

Ok.

Answer 45

what do i do now?

Answer 46

What did you do so far?