#How can i simplify expressions like this?

47 messages · Page 1 of 1 (latest)

past salmonBOT
shell dust
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full expression:
(1+y) + (2+y)y + (3+y)y^2 ... ( (c-1) + y )*y^(c-2)

past salmonBOT
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How can i simplify expressions like this?

sinful lava
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think of teach term in this series as (1 + y), (2 + y)y, (3 + y)yˆ2...

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now lets get this in a form thats easier to work with

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we can rewrite (2 + y)y as y + (1 + y)y, and (3 + y)yˆ2 as 2yˆ2 + (1 + y)y^2

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so now our terms look like
1 + y

  • y + (1 + y)y
  • 2y^2 + (1 + y)y^2
  • 3y^3 + (1 + y)y^3
  • ...
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so what can we do with this now to simplify it

shell dust
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ohhhh

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lemme try

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(1+y)
y + (1 + y)y
2y^2 + (1+y)^2
...
(c-2)y^(c-2) + (1+y)^(c-2)

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this right?

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@sinful lava

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(c-2)y^(c-2) + (1+y)*y^(c-2)

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y^(c-2) ( (c-2) + (1 +y) )
y^(c-2) ( c-1 + y)

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yes this is right

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1 + y
y + (1 + y)y
2y^2 + (1 + y)y^2
3y^3 + (1 + y)y^3
...
(c-2)y^(c-2) + (1+y)*y^(c-2)

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1 + y
y + (1 + y)y
2y^2 + (1 + y)y^2
3y^3 + (1 + y)y^3
...
(c-2)y^(c-2) + (1+y)*y^(c-2)

lets separate this

y + 2y^2 + 3y^3 ... + (c-2)y^(c-2) +
(1+y) + (1+y)y + (1+y)y^2 ... (1+y)^(c-2)

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just use the formule on the below

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s = (1+y) + (1+y)y + (1+y)y^2 ... (1+y)^(c-2)
s = (1+y) * ( y^(c-1) -1)/(y-1)

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now
we got

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y + 2y^2 + 3y^3 ... + (c-2)y^(c-2) + (1+y) * ( y^(c-1) -1)/(y-1)

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how can i factor the other sum?

shell dust
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like

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theres no common multiples ( only y but i cant do anything with it)

sinful lava
shell dust
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oh

sinful lava
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z is the solution to the other sum

shell dust
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alr

sinful lava
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this is for the infinite form though

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i have to go now but

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hopefully this is enough for you

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to do the finite form

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cya man

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and i pray that this is not on your test

shell dust
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what im trying to do is proof compound interest formula

sinful lava
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ohh ok i see

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alr bye bro

shell dust
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u iwll close?

sinful lava
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no dont close yet

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close once you solved it fully

shell dust
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sure

sinful lava
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just incase you have other questions for anyone else to answer

shell dust
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alr

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thanks man