Find the sum of the first n odd integers?

Question

Find the sum of the first n odd integers.
1 + 3 + 5 + … + 201


a)10201
b)5050
c)5151
d)20301


*10pts to correct answers

Answer 1

An = d(n-1) + a1
An = 2(n- 1) + 1
An = 2n - 2 + 1
An = 2n - 1

201 = 2n - 1
202 = 2n
n = 101

sum = 101 (1 + 201) / 2
sum = 10201

A

Answer 2

We know that the nth term

an = a1 + (n-1) d

201 = 1 + (n-1) 2

201 = 1 + 2n - 2

202 = 2n or n = 101

We use that to calculate

sn = n (a1 + an) / 2

sn = 101 (202)/ 2 = 101^2 = 10201

So, a is the right answer.

Answer 3

I think it's a, 10201 because first I found the average, 101, then I multiplied it by the amount of odd numbers between those two numbers, 101. So 101^2 or 10201

Answer 4

tn = a + (n-a million) d fifty seven = a million + (n-a million) 2 fifty seven = a million + (2n-2) fifty seven = 2n - a million fifty 8 = 2n 29 = n Sn = n/2 [2a+(n-a million)d] S(29) = 14.5 [2(a million) + 28 (2)] S(29) = 14.5 [fifty 8] S(29) = 841 the respond is D. 841.