Step-by-step explanation:
Given the Arithmetic sequence
An arithmetic sequence has a constant difference d and is defined by
as
∵
∵ 
∵ 
Therefore, the indicated nth partial sum of the arithmetic sequence is 1530.
ANOTHER METHOD
as
n = 30
as
and
so
Answer:
Melanie = 24 years old
Raymond = 27 years old
Step-by-step explanation:
Please let me know if you want me to add an explanation as to why this is the answer. I can definitely do that, I just wouldn’t want to write it if you don’t want me to :)
This is the concept of algebra, to solve the expression we proceed as follows;
cos 2x-cosx=0
cos 2x=cosx
but:
cos 2x+1=2(cos^2x)
thereore;
from:
cos 2x=cos x
adding 1 on both sides we get:
cos 2x+1=cos x+1
2(cos^2x)=cosx+1
suppose;
cos x=a
thus;
2a^2=a+1
a^2-1/2a-1/2=0
solving the above quadratic we get:
a=-0.5 and a=1
when a=-0.5
cosx=-0.5
x=120=2/3π
when x=1
cos x=1
x=0
the answer is:
x=0 or x=2/3π
Answer:
your answer is c
Step-by-step explanation:
Answer:
9
Step-by-step explanation:
80% of 45 is 36
45-36=9
