Question

Find the sum of the G.P,1+2+3+...+45

Answer 1

Answer:

hello :

note : 1+2+3+.......+n = n(n+1)/2

Step-by-step explanation:

in this exercice : n = 45

1+2+3+...+45 = 45×46/2 = 1035

Answer 2

Answer:   1035

Step-by-step explanation:

$\sum^{45}_{1}i\\\\\text{The sum of an arithmetic sequence is:}\ \dfrac{a_1+a_n}{2}\cdot n\\\\= \dfrac{1+45}{2}\cdot 45\\\\\\=\dfrac{46}{2}\cdot 45\\\\\\=23\cdot 45\\\\=1035$