Question

the sum of first 30 odd number is​

Answer 1

HELLO DEAR FRND

   HOPE THIS WILL HELP U

Let’s try to SOLVE IT together.

FIRST OBSERVE THE PATTEREN

1 = 1

1+3 = 4

1+3+5 = 9

1+3+5+7 = 16

1+3+5+7+9 = 25

WE CAN SEE FROM ABOVE

If n = number of first odd numbers:

   n=1, sum = 1

   n=2, sum = 4

   n=3, sum = 9

   n=4, sum = 16

   n=5, sum = 25

Hmmm…I see a pattern, do you?

n=1, sum = 1, which is 1²

n=2, sum = 4, which is 2²

n=3, sum = 9, which is 3²

n=4, sum = 16, which is 4²

n=5, sum = 25, which is 5²

Based on our observation, the summation of the n first odd numbers is equal to n².

So, to directly answer the question, we substitute 30 for n.

30²=900

∴Sum of the first 30 odd numbers=900

Answer 2

The number series 1, 3, 5, 7, 9, . . . . , 59.

The first term a = 1

The common difference d = 2

Total number of terms n = 30

Step 2 :

apply the input parameter values in the AP formula

Sum = n/2 x (a + Tn)

= 30/2 x (1 + 59)

= (30 x 60)/ 2

= 1800/2

1 + 3 + 5 + 7 + 9 + . . . . + 59 = 900

Therefore, 900 is the sum of first 30 odd numbers.