Can any body here prove that 1-1+1-1+1-1+1-1=1/2
And What is known as this series?

This is known as grandi's series, the proof is in the explanation

Step-by-step explanation:

grandi's series, is given by = 1-1+1-1+1-1+1-1...

1 - = 1 - (1-1+1-1+1-1+1-1) = 1-1+1-1+1-1+1-1 =

1- =

+ = 1

2 = 1

= 1/2

This is known as grandi's series, the proof is in the explanation

Step-by-step explanation:

grandi's series,  is given by = 1-1+1-1+1-1+1-1...

1 -  = 1 - (1-1+1-1+1-1+1-1) = 1-1+1-1+1-1+1-1 =  

1-  =  

+  = 1

2 = 1

= 1/2

Step-by-step explanation:

x = -3

y = -18

step-by-step explanation:

to solve by substitution, substitute one variable and solve for the other. then substitute again to find the remaining variable.

x-1/3(3x-9) = -3 since y=3x-9 substittute y.

x-1/3(3x-9)=-3

x + x +3 = -3

2x+3=-3

2x+3-3= -3-3

2x=-6

x=-3

substitute again into y=3x-9

y=3(-3)-9

y=-9-9

y=-18