document.write( "Question 1061883: 1-(1/4)+(1/9)-(1/16)+(1/25)-............=?
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Algebra.Com's Answer #676671 by ikleyn(52794) $\"\"$ $\"About$

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document.write( "Well known fact (after Euler) is \r\n" );
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document.write( "S = 1 + (1/4) + (1/9) + (1/16) + (1/25) + (1/36) + . . .  =            (1)\r\n" );
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document.write( "The sum of the even terms is \r\n" );
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document.write( "E =     (1/4) +         (1/16) +          (1/36) + . . . = \r\n" );
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document.write( "        (1/4)*(1 +      (1/4) +          (1/9) + . . . ) =     (2)\r\n" );
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document.write( "What the problem actually asks about is the difference  S - 2E =  - .( = . = . = .\r\n" );
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Answer. $\"pi%5E2%2F12\"$ .\r
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