Question

find the sum of the following series 1+4+9+16+...+225​

Answer 1

the series is 1²+2²+3²+4²+........+15²

by using formula

1²+2²+..........+n² = n(n+1)(2n+1)/6

where n= 15

so, sum of series is

15(15+1)(2×15+1)/6

= 15×16×31/6

= 5×8×31

=40×31 = 1240

i hope it will be helpful for u

Answer 2

Answer:

Step-by-step explanation:

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