Question

show that a1, a2.....an .....form an appointment where an is defined as below: an=9-5n

Answer 1

a1=9-5(1)
=9-5=4
a2=9-5(2)
=9-10=-1
a3=9-5(3)
a3=9-15=-6
d=a3-a2=a2-10a1
d=-6-(-1)=-1-4
d=-6+1=-5
an=a+(n-1)d
=4+(n-1)-5
=4+5n-5
an =5n-1