The sum of n 2n 3n terms of an AP are S1 S2 S3 respectively. Prove that S3=3(S2-S1).

Dear Student!

Here is the answer to your question.

Let the first term of the A.P. be *a* and the common difference be *d*.

According the question,

We have to prove that S_{3} = 3 ( S_{2} – S_{1}).

R.H.S = 3 (S_{2} – S_{1})

= S_{3}

= L.H.S

⇒ S_{3} = 3 ( S_{2} – S_{1})

Cheers !

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