The fourth term of an exponential sequence is 108 and the ratio is 3 . Calculate the value of the eighth term of the sequence, calculate the sum of the first five terms of the sequence.

8th term = 8748 , Sum of 5 terms = 484

Step-by-step explanation:

Formula for nth term in an exponential sequence = a r^ (n-1)

Here : n = 4 , ratio r = 3 ; And nth ie 4th number = 108

So,  a r^ (n-1) = nth item implies that → a 3 ^ (4-1) = 108

a 3^3 = 108 →  27 a = 108 → a = 108 / 27 → a = 4

8th term = a r^ (n-1) , at  n = 8.  So, = 4 3^(8-1) = 4 3^7 = 4 x 2187 = 8748

Sum of n terms = a [(r^n) -1 ] / [r - 1] → Sum 5 terms = 4 [ (3^5)- 1] / [3 - 1]

= 4 [ (243) - 1] / 2 ] = 2 x 242 = 484

it is true

step-by-step explanation:

all the combinations add up i used   calculator

solution:

the given function is ,

      =

the three roots of this quadratic function is , 0 ,8 and 10.all the roots are real and rational.

if a quadratic equation is of the form ,

sum of the roots = a + b +c= 0+8+10=18=  

product of roots taken two at a time = a b + b c+ c a = 0+80+0=80 =  

product of roots = a b c = 0=  

there are 11 doors in a hall starting from 0 to 11.the entry in the hall is permitted through gate number 0 and exit is allowed through only gate number 8 and 10.so, three roots(0,8,10) of quadratic function is given by entry and exit route of this hall.