Question

Which sequence represents an arithmetic sequence?

Answer 1

we know that

arithematic sequence will always have common difference

(a)

−5, −7, −10, −14, −19, …

we can see that

$d_1=-7+5=-2$

$d_2=-10+7=-3$

they are not equal

so, this is not arithematic sequence

(2)

1.5, −1.5, 1.5, −1.5, …

we can see that

$d_1=-1.5-1.5=-3$

$d_2=1.5+1.5=3$

they are not equal

so, this is not arithematic sequence

(3)

4.1, 5.1, 6.2, 7.2, …

we can see that

$d_1=5.1-4.1=1$

$d_2=6.2+5.1=1.1$

they are not equal

so, this is not arithematic sequence

(4)

−1.5, −1, −0.5, 0, …

we can see that

$d_1=-1+1.5=0.5$

$d_2=-0.5+1=0.5$

they are equal

so, this is arithematic sequence