Question

an arithmetic sequence with common difference 6, ninth term is zero. ( a) Find 8th term and 10th term?

Answer 1

Step-by-step explanation:

hope it helps u.......

Answer 2

ANSWER:

• 8th term = - 6

• 10th term =  6

GIVEN:

• An arithmetic sequence with common difference 6.

• Ninth term is zero.

TO FIND:

• 8th term.

• 10th term.

EXPLANATION:

$\boxed{\bold{\large{T_n = a + (n - 1)d}}}$

$\sf T_9 = 0$

d = 6

a + (9 - 1)6 = 0

a + 8(6) = 0

a = - 48

$\sf T_8 = -48 + (8 - 1)6$

$\sf T_8 = -48 + (7)6$

$\sf T_8 = -48 + 42$

$\sf T_8 = -6$

$\sf T_{10} = -48 + (10 - 1)6$

$\sf T_{10} = -48 + (9)6$

$\sf T_{10} = -48 + 54$

$\sf T_{10} = 6$

HENCE THE 8TH TERM = - 6 AND THE 10 TH TERM = 6

Some more formulae:

$\boxed{\bold{\bold{S_n=\dfrac{n}{2}(2a+(n-1)d)}}}$

$\boxed{\bold{\bold{S_n=\dfrac{n}{2}(a+l)}}}$

$\boxed{\bold{\bold{n=\dfrac{l-a}{d}+1}}}$