Question

if 2+5+7+9...to n=143 is a parallel series then find n​

Answer 1

Answer:

wrong question ...the series should be

• 3+5+7+9+....+n'th term=143

question clear Karo tavi answer jaldi milega.....xD....

$143 = \frac{n}{2} (2 \times 3 + (n - 1)2) \\ 286 = 6n + 2n {}^{2} - 2n \\ 2n {}^{2} + 4n - 286 = 0 \\ n {}^{2} + 2n - 143 = 0 \\ n {}^{2} + 13n - 11n - 143 = 0 \\ n(n + 13) - 11(n + 13) = 0 \\ (n - 11)(n + 13) = 0 \\ \\ therefore \: \: \: \: (n - 11) = 0 \\ n = 11 \\ \\ or \: (n + 13) = 0 \\ n = - 13 \\ \\ now \: \: n \: can \: not \: be \: a \: negative \: number \: \: \: so \: \: \: \: \\ so \\ n = 11 \: \: is \: taken$

the value of n=11