1) 1/2, 1/7, 1/12, 1/17… ( kapag po kase harmonic sequence or progression, kinukuha lang po yung reciprocal ng arithmetic, kaya naging 1/2, 1/7 and so on. Explaination po pala sa arithmetic sequence na 'yan kung bakit 2, 7, 12, 17 kase nag a-add po tayo ng 5 to the previous number. Kaya ang common difference is 5 )2) 25, 22, 19, 16 ( tinanggal lang po natin yung 1 dahil po ang gagawin is arithmetic sequence, since descending po yung, negative po magiging common difference niya, bali magiging -3 )sa 3 and 4 naman po ganun din. hindi ko lang po alam ano formula ng harmonic sequence e, ganyan lang idea ko.etoo naman po sa 5, tinry ko langg