[ ( x + 4 )( x + 5 ) + 4( x + 1 )( x + 5) - 5( x + 1 )( x + 4 ) ] / [( x + 1 )( x + 4)( x + 5 )] = ( x^2 + 9x + 20 + 4x^2 + 24x +20 - 5x^2 - 25x - 20) / [( x + 1 )( x + 4)( x + 5 )] =
( - 2x + 20 ) / [( x + 1 )( x + 4)( x + 5 )] = ( - 2)( x - 10) / [( x + 1 )( x + 4)( x + 5 )]

4 0

3 years ago

The first term of a geometric sequence is 6 and the fourth term is 384. What is the sum of the first 10 terms of the correspondi

aleksandrvk [35]

Answer:

2097150

Step-by-step explanation:

GIVEN :-

First term of G.P. = 6
Forth term of G.P. = 384

TO FIND :-

Sum of first 10 terms of the G.P.

CONCEPT TO BE USED IN THIS QUESTION :-

Geometric Progression :-

It's a sequence in which the successive terms have same ratio.

General form of a G.P. ⇒ a , ar , ar² , ar³ , ....... [where a = first term ; r = common ratio between successive terms]

Sum of 'n' terms of a G.P. ⇒ $\frac{a(r^n - 1)}{r-1}$ .

[NOTE :- $\frac{a(1-r^n)}{1-r}$ can also be the formula for "Sum of n terms of G.P." because if you put 'r' there (assuming r > 0) you'll get negative value in both the numerator & denominator from which the negative sign will get cancelled from the numerator & denominator. YOU'LL BE GETTING THE SAME VALUE FROM BOTH THE FORMULAES.]