Question

1+3+5+..........+201 Ajutatima  va rog!!!

Answer 1

1+3 +5 +.............+201
n= ( 201 - 1) : ( (3-1) +1
n = 200 : 2 +1
n = 100+1
n= 101

S= [(201+1) ×101 ]:2
S= (202 ×101 ) :2
S= 20 402 :2
S= 10 201.

Answer 2

(2*1-1)+(2*2-1)+(2*3-1)+...+(2*101-1)=
=2(1+2+3+...+101)-1*101=
=2*101*102:2-101=
=101*102-101=
=101(102-1)=
=101*101=
=10201