Question

Find the fifth term of the arithmetic sequence in which t1 = 3 and tn = tn-1 + 4. A) 5 B) 7 C) 19 D) 23 2) Find the tenth term of the arithmetic sequence in which t1 = 2 and t4 = -10. A) -10 B) -34 C) -38 D) -106 3) Find the fifth term of the geometric sequence in which t1 = 3 and tn = 2tn-1. A) 5 B) 6 C) 48 D) 96

Answer 1

We know that

Part a) Find the fifth term of the arithmetic sequence in which t1 = 3 and tn = tn-1 + 4
t1=3
t2=t1+4----> 3+4-----> 7
t3=t2+4-----> 7+4----> 11
t4=t3+4-----> 11+4---> 15
t5=t4+4-----> 15+4---> 19

the answer Part a) is 19

Part b) Find the tenth term of the arithmetic sequence in which t1 = 2 and t4 = -10

we know that 
tn=t1+(n-1)*d-----> d=[tn-t1]/(n-1)
t1=2
t4=-10
n=4
find the value of d
d=[-10-2]/(4-1)-----> d=-12/3----> d=-4
find the tenth term (t10)
t10=t1+(10-1)*(-4)----> t10=2+9*(-4)----> t10=-34

the answer Part b) is -34

Part c) Find the fifth term of the geometric sequence in which t1 = 3 and tn = 2tn-1
t1=3
t2=2*t1----> 2*3----> 6
t3=2*t2----> 2*6----> 12
t4=2*t3-----> 2*12---> 24
t2=2*t4----> 2*24----> 48

the answer Part c) is 48