1. 1³+2³+3³+__+9³: 2.1³+2³+3³+4³5³+6³+__+14³:

#1
= (1 + 2 + 3 + ... + 9)²
= ((1 + 9) x (9/2))²
= (10 x 4,5)²
= 45²
= 2.025

#2
= (1 + 2 + 3 + ... + 14)²
= ((1 + 14) x (14/2))²
= (15 x 7)²
= 105²
= 11.025

Maaf kalau salah
Semoga benar dan membantu^^

Materi: Notasi Sigma

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