if 9th term of AP is zero ,prove that it\'s 29th term is double of its

1.	if 9th term of AP is zero ,prove that it\'s 29th term is double of its 19th term.
Answer» a9=a+8d=0 ............. ia29=a+28d..................iia19=a+18d..................iiifrom i and iia= - 8da29= - 8d + 28d a29 = 20d ..... ivfrom i and iiia19 = - 8d + 18d = 10d ... vthus a29 is double of a19 (20d is double of 10d) ...... proved a9=0a + 8d = 0a= -8d ............... (I)Now, a29 = a + 28d = -8d + 28d = 20dAgain, a19= a + 18 d = -8d + 18d =10dHence, 29th term is double of its 19th term.

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