Prove this by MI.

∑_(r=1)^3▒1/3^r = 1/2 - 1/(2(3^n))

How do I display this properly? I write from MS words and paste here. I try wrapping with Math tag but it wont work.

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- January 20th 2009, 11:18 PMazukiMathematic induction Question 2
Prove this by MI.

∑_(r=1)^3▒1/3^r = 1/2 - 1/(2(3^n))

How do I display this properly? I write from MS words and paste here. I try wrapping with Math tag but it wont work. - January 20th 2009, 11:36 PMJhevon
We proceed by mathematical induction.

Let for all

is true, since

Assume is true, we now show that this implies is true.

Since is true, we have

Then

.

.

.

i leave it to you to finish up. my last line was a crucial hint

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How do I display this properly? I write from MS words and paste here. I try wrapping with Math tag but it wont work.