A statement Sn about the positive integers is given. Write statements S1, S2, and S3, and show that each of these statements is true.

Sn: 2 + 5 + 8 + . . . + ( 3n - 1) = n(1 + 3n)/2

I Got
S1: 2 = 1(3 ・ 1 + 1) /2

2 =1 ・ 4 / 2
2 = 2

My teacher says my calculations have arithmetic errors

Question

A statement Sn about the positive integers is given. Write statements S1, S2, and S3, and show that each of these statements is true. 

Sn:    2 + 5 + 8 + . . . + ( 3n - 1) = n(1 + 3n)/2

I Got 
S1: 2 = 1(3 ・ 1 + 1) /2
 
2 =1 ・ 4  / 2
2 = 2 

My teacher says  my calculations have arithmetic errors

anonymous · Answer

@ybarrap could you help me out please

ybarrap · Answer

S1= 1(1 + 3)/2= 4/2 = 2
S2 = 2(1 + 3*2)/2 = 7
S3 = 3(1 + 3*3)/2=3(10)/2 = 15

So, S1=2, S2=7 & S3=15.

Does this make sense?

anonymous · Answer

yea

anonymous · Answer

Thank You :)

ybarrap · Answer

NP

ybarrap · Answer

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