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mtayab1994
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Homework Statement
Sn=1-3+5-7...+(-1)^n(2n+1)
Homework Equations
Show that Sn=(-1)^n(n+1)
The Attempt at a Solution
S(n+1)=Sn+(-1)^(n+1)*(2n+3) = (-1)^n*(n+1)+ (-1)^(n+1)*(2n+3)
S(n+1)= (-1)^(n+1)*[(2n+3)-(n+1)] (because (-1)^(n+1)= - (-1)^n )
S(n+1)=(-1)^(n+1)*(n+2)
is that correct proof
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