k(k+1)/2=1+2+3+4+5+...+khasil dari sigma diatas adalah(1+2+3+4+5)+(1+2+3+4+5+6)+(1+2+3+4+5+6+7)+....+(1+2+3+4+...+n)=(n-5+1)(1+2+3+4+5) +(6+7+8+9+...+n)=(n-4)(15) +(n-6+1)(6+n)/2=15n-60 +(n-5)(n+6)/2=15n-60 +(n²+n-30)/2=(30n-120+n²+n-30)/2=(n²+29n-150)/2
" Life is not a problem to be solved but a reality to be experienced! "
© Copyright 2013 - 2025 KUDO.TIPS - All rights reserved.
k(k+1)/2=1+2+3+4+5+...+k
hasil dari sigma diatas adalah
(1+2+3+4+5)+(1+2+3+4+5+6)+(1+2+3+4+5+6+7)+....+(1+2+3+4+...+n)
=(n-5+1)(1+2+3+4+5) +(6+7+8+9+...+n)
=(n-4)(15) +(n-6+1)(6+n)/2
=15n-60 +(n-5)(n+6)/2
=15n-60 +(n²+n-30)/2
=(30n-120+n²+n-30)/2
=(n²+29n-150)/2