Question

What is the first four terms of the A.P. whose first term is $-1$ and common difference is $0.5$?

• A. $0.5,0,0.5,-2.....$
• B. $-0.5,0,0.5,2.....$
• C. $-0.5,0,0.5,1.....$
• D. $-0.5,0,0.5,-1.....$

Answer 1

The correct option is C $-0.5,0,0.5,1.....$

Let the series be $a_1,a_2,a_3,a_4,a_5.....$
$a_1=a=-1$
Common difference $=0.5$
$a_2=a_1+d=-1+0.5=-0.5$
$a_3=a_2+d=-0.5+0.5=0$
$a_4=a_3+d=0+0.5=0.5$
$a_5=a_4+d=0.5+0.5=1$
Therefore, first four terms of this A.P. will be $-0.5,0,0.5,1.......$