write an explicit formula for the equation 4,1.5,-1,-3.5.....
This is an AP
the common diff is -2.5
Tn=a+(n-1)d
Tn=4+(n-1)*-2.5
Tn=4+-2.5(n-1)
Tn=4-2.5n+2.5
Tn=6.5 - 2.5n