What is the sum of the first 30 even numbers?show me what is the formula.?

Question

What is the sum of the first 30 even numbers?show me what is the formula.?

Answer 1

2 + 4 + 6 + ... + 60

= 2(1 + 2 + 3 + ... + 30)

= 2 30 X 31/2

= 930.

Formula for sum of even numbers upto the last number n is

(n/2)(n/2+1).

Answer 2

sum of numbers = n/2[2a + (n – 1)d]

where n = total numbers = 30

a = first number = 2

d = common difference in numbers (here) = 2

sum = 30/2[2 × 2 + 2(30 – 1)]

= 15 × [4 + 58]

= 15 × 62 = 930

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Answer 3

2+4+6+8+9+10+12+14+16+18+20+22+24+26+28+...

your sum is 870

Answer 4

f(x) = x(x + 1)

f(30) = 30(30 + 1)

f(30) = 30(31)

f(30) = 930