document.write( "Question 998264: Find the sum of first 15 terms of an AP., whose nth term is 3-2n. \n" ); document.write( "

Algebra.Com's Answer #616079 by mananth(16946) $\"\"$ $\"About$

You can put this solution on YOUR website!

\n" ); document.write( "nth term = 3-2n\r
\n" ); document.write( "\n" ); document.write( "t1= 3-2=1\r
\n" ); document.write( "\n" ); document.write( "t2= 3-4=-1\r
\n" ); document.write( "\n" ); document.write( "t3=3-6 = -3\r
\n" ); document.write( "\n" ); document.write( "The AP is 1,-1,-3 .........\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "here a = 1, d= -2 , n=15\r
\n" ); document.write( "\n" ); document.write( "Sn = $\"+%28n%2F2%29%282a%2B%28n-1%29d%29\"$ \r
\n" ); document.write( "\n" ); document.write( "S 15 = $\"+%2815%2F2%29%282%281%29%2B%2815-1%29%2A%28-2%29%29\"$ \r
\n" ); document.write( "\n" ); document.write( "S15 = $\"%2815%2F2%29+%2A+-26\"$ \r
\n" ); document.write( "\n" ); document.write( "= -13*15\r
\n" ); document.write( "\n" ); document.write( "=-195\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "

\n" );