Question

21st term of an arithmetic sequence 21, 20, 19........

Answer 1

Answer:

AP = 21, 20, 19, ...................

21st term ( a21 ) = ?

first term ( a1 )= 21

a2 = 20

difference ( d ) = a2 – a1

= 20 – 21

= –1

a21 = a + 20d

= 21 + 20*–1

= 21 – 20

= 1

the 21st term of an AP is 1.