Question

Ex. 15 va rog frumos!
Multumesc :)

Answer 1

51+52+1003+150+151=507
101 :507

Answer 2

15.

a) S=51+52+...+150+151

S=$\frac{n(n+1)}{2}$

S=$\frac{151(151+1)}{2}$

S=$\frac{151·152}{2}$

S=$\frac{22952}{2}$

S=11476

b)

$101^{n}$=1+2+3+4+...+101

$101^{n}$=$\frac{n(n+1)}{2}$

$101^{n}$=$\frac{101(101+1)}{2}$

$101^{n}$=$\frac{101·102}{2}$

$101^{n}$=$\frac{10302}{2}$

$101^{n}$=5151