.
(a)
(i) T1 is the first term, which is 3.
S1 is the first term, which is 3, again.
T2 is the second term, which is 7.
S2 is the sum of the first two terms, which is 3+7 = 10.
(ii) T2 = S2 - S1, which is OBVIOUS.
(iii) T4 is the 4th term 15.
S4 is the sum of the first 4 terms 3 + 7 + 11 + 15.
(calculate it on your own, if you need)
(iV) T3 = S3 - S2.
which means that the third term of the AP is the sum of the first 3 terms MINUS the sum of the first two terms.
If you think one minute, you will find this formula OBVIOUS and trivial.
And the last assignment /formula is
T100 = S100 - S99.
It expresses that obvious fact that the 100th term is the sum of the first 100 terms MUNIS the sum of the first 99 terms.
Happy learning (!)
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For introductory lessons on arithmetic progressions see
- Arithmetic progressions
- The proofs of the formulas for arithmetic progressions
- Problems on arithmetic progressions
- Word problems on arithmetic progressions
in this site.
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- ALGEBRA-II - YOUR ONLINE TEXTBOOK.
The referred lessons are the part of this online textbook under the topic "Arithmetic progressions".
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Free of charge online textbook in ALGEBRA-II
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