Answer:
The sum of 8 geometric sequence is 959780
Step-by-step explanation:
We are given
this sequence is geometric
-4 , 24 , -144
First term is -4
so,
now, we can find common ratio
we can use formula
n=8
now, we can plug values
now, we can simplify it
and we get
Answer with explanation:
Number of four digit numbers using four distinct digit
=Unit placed can be filled in four ways * Tens place can be filled in Three ways * Hundreds place can be filled in 2 ways * Thousand Place can be filled in a single way
=4*3*2*1
=24 distinct numbers
Sum of all four , four digits numbers using 1,2,3,4
= (If we keep 4 at unit place +Keeping 3 at unit place +Keeping 2 at unit place+Keeping 1 at unit place)×6+At tens place (2*2+3*2+1*2+4*2+2*2+1*2+1*2+3*2+4*2+2*2+3*2+4*2)+At hundred's place (2*2+3*2+1*2+4*2+2*2+1*2+1*2+3*2+4*2+2*2+3*2+4*2)+At thousand's Place(2*2+3*2+1*2+4*2+2*2+1*2+1*2+3*2+4*2+2*2+3*2+4*2)
=(24+18+12+6)Unit place+(60)Ten's place +(60)Hundred's place+(60)Thousand's Place
=66660
