document.write( "Question 1141231: please help me with this mathematical induction 1/2^1+1/2^2+1/2^3+....+1/2^n =1-1/2^n. \n" ); document.write( "
Algebra.Com's Answer #761801 by math_helper(2461)\"\" \"About 
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please help me with this mathematical induction 1/2^1+1/2^2+1/2^3+....+1/2^n =1-1/2^n.
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\n" ); document.write( "please help me by proving this statement using mathematical induction \"1%2F2%5E1%2B1%2F2%5E2%2B1%2F2%5E3+\" + ... + \"+1%2F2%5En+=+1-1%2F2%5En\".
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\n" ); document.write( "n=1: \"+1%2F2%5E1+=+1%2F2+=+1-1%2F2%5E1+\" Ok for n=1. This is the base-case. \r
\n" ); document.write( "\n" ); document.write( "Assume it is true for n=k: that is, \"+1%2F2%5E1+%2B+1%2F2%5E2+\" + ... + \"+1%2F2%5En+\" = \"+1-1%2F2%5En+\" holds for n=k. This is the hypothesis statement.\r
\n" ); document.write( "\n" ); document.write( "Now look at the case n=k+1:\r
\n" ); document.write( "\n" ); document.write( "\"+1%2F2%5E1+%2B+1%2F2%5E2+\" + ... + \"+1%2F2%5Ek+%2B+1%2F2%5E%28k%2B1%29+\" \r
\n" ); document.write( "\n" ); document.write( "If we exclude the very last term for a second, the remainder is the same case as n=k, which we can re-write by applying the hypothesis:\r
\n" ); document.write( "\n" ); document.write( "= \"+1+-+1%2F2%5Ek+\" + \"+1%2F2%5E%28k%2B1%29+\"\r
\n" ); document.write( "\n" ); document.write( "Putting everthing over a common denominator (step-by-step):
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\n" ); document.write( "\n" ); document.write( "= \"+%282%5E%28k%2B1%29+-+2+%2B+1%29+%2F+2%5E%28k%2B1%29+\"\r
\n" ); document.write( "\n" ); document.write( "= \"+%282%5E%28k%2B1%29+-+1%29+%2F+2%5E%28k%2B1%29+\"\r
\n" ); document.write( "\n" ); document.write( "Dividing the numerator by the denominator:
\n" ); document.write( "= \"+1+-+%281%2F2%5E%28k%2B1%29%29+\" DONE (the hypothesis leads to truth for n=k+1)\r
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