Question

if 9th term of an ap is zero, prove that its 29th term is double of 19th term
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Answer 1

Answer:

• a+8d=0. eqn 1
• a29=2(a19)
• a+28d=2(a+18d)
• a+28d=2a+36d
• a-2a+28d-36d=0
• -a-8d=0
• -a=8d
• a+8d=0. eqn 2
• Subtract equation 1 from 2
• (a+8d)-(a+8d)=0
• a+8d-a-8d=0
• Therefore,0=0
• Hence,proved