Math, asked by Anonymous, 1 year ago

If 3 times the 4th term of an A.P is equal to 9 times its 10th term , then show that its 23rd term is zero.

siddhartharao77: I think it should be its 13th term is zero.

rohitkumargupta: yes Bhai

rohitkumargupta: not 23rd term

LuHan03: yeah, it should be 13th term : )

Answers

Answered by rohitkumargupta

HELLO DEAR,

I THINK SOMETHING MISTAKE IN YOUR QUESTIONS

RIGHT QUESTIONS IS LIKE THAT

If 3 times the 4th term of an A.P is equal to 9 times its 10th term , then show that its 13rd term is zero.

given:-

Let a=First term
d=common difference
$3( t_{4}) = 9( _{10}) \\ = > a + 3d = 3a + 27d \\ = > - 24d = 2a \\ = > a = - 12d ......(1)\\ = > t_{13} = a + 12d \\ = > - 12d + 12d = 0 \\ = > t_{13} = 0$

.

Anonymous: no , in the sample paper ,its like tht only .,. no mistakes..

Róunak: Then, check my solution.

rohitkumargupta: then something is mistake kindly chek your questions dear plz

Róunak: Yeah...plz..do check

rohitkumargupta: yes

siddhartharao77: Kindly correct the steps bro, They are incorrect

Answered by Róunak

Hey mate..
========

Given,

If 3 times the 4th term of an A.P is equal to 9 times its 10th term.

So,

3 × a(4) = 9 × a(10)

=> 3 ( a + 3d ) = 9 ( a + 9d )

=> 3a + 9d = 9a + 81d

=> 3a - 9a = 81d - 9d

=> -6a = 72d

=> a = -12d....(1)

Now,

a(23) = a + 22d

= -12d + 22d [ From (1) ]

= 10d

•°•a(23) is not equal to zero

Kindly Check your question.

Anonymous: we have to prove tht it is equal to zero..

Róunak: Plz...Check my solution !! It is correct

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