Question

1+3+5+7+9+11+13+15...... के 15 पदों तक का योगफल कितना होगा

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Answer 1

Answer:-

Given:

1 , 3 , 5..... are in AP.

Hence,

• a (first term) = 1
• d (common difference) = 3 - 1 = 2

We know that,

Sum of first n terms of an AP (Sn) = n/2 * [2a + (n - 1)d]

Hence,

→ S(15) = (15/2) * [ 2(1) + (15 - 1)(2) ]

→ S(15) = 15/2 * (2 + 28)

→ S(15) = 15/2 * 30

→ S(15) = 225

Hence, the sum of first 15 terms of the given series is 225.

Additional Information:-

• A series in which each term (except first term) differs from its preceding term by a fixed quantity is called an Arithmetic Progression (AP).

• The fixed quantity is called common difference.

• General form of an AP is a , a + d .... if a is the first term and d is the common difference.

• nth term of an AP is a + (n - 1)d.

Answer 2

Explanation:

1+3+5+7+9+11+13+15...... के 15 पदों तक का योगफल कितना होगा