Question

if 10th term is 9and 9th term is 10 then the common difference is
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Answer 1

Answer:

The common difference .

\begin{gathered}\red{\frak{Given}}\begin{cases}\textsf{ 10th term of the AP is 9 .}\\\textsf{ 9th term of an AP is 10.} \end{cases}\end{gathered}

Given{

10th term of the AP is 9 .

9th term of an AP is 10.

We can use the formula to find the nth term of a. AP .Let the first term of the AP be a and Common Difference be d .

• According to first Condition :-

\begin{gathered}\sf:\implies T_n = a + (n-1)d \\\\\sf:\implies T_{10 }= a + (10-1)d \\\\\implies \boxed{\frak{ 9 = a + 9d }}\cdots\cdots (i) \end{gathered}

:⟹T

n

=a+(n−1)d

:⟹T

10

=a+(10−1)d

⟹

9=a+9d

⋯⋯(i)

• According to second Condition :-

\begin{gathered}\sf:\implies T_n = a + (n-1)d \\\\\sf:\implies T_{9}= a + (9-1)d \\\\\implies \boxed{\frak{ 10 = a + 8d }}\cdots\cdots (ii) \end{gathered}

:⟹T

n

=a+(n−1)d

:⟹T

9

=a+(9−1)d

⟹

10=a+8d

⋯⋯(ii)