Step-by-step explanation:
t8 = a1 + (n - 1)*d
t8 = 17
17 = a1 + 7*d
t12 = 25
25 = a1 + 11d
17 = a1 + 7d Subtract
8 = 4d Divide by 4
8/4 = 4d/4
2 = d
17 = a1 + 7d
17 = a1 + 7*2
17 = a1 + 14 Subtract 14
3 = a1
Sum 20 terms
The 20 term = a1 + 19*2
The 20 term = 3 + 38
= 41
Sum = (a1 + a20) * 20 / 2
Sum = (3 + 41)* 20/2
Sum = 44 * 10
Sum = 440
Answer with Step-by-step explanation:
We are given that A and B are two countable sets
We have to show that if A and B are countable then
is countable.
Countable means finite set or countably infinite.
Case 1: If A and B are two finite sets
Suppose A={1} and B={2}
={1,2}=Finite=Countable
Hence,
is countable.
Case 2: If A finite and B is countably infinite
Suppose, A={1,2,3}
B=N={1,2,3,...}
Then,
={1,2,3,....}=N
Hence,
is countable.
Case 3:If A is countably infinite and B is finite set.
Suppose , A=Z={..,-2,-1,0,1,2,....}
B={-2,-3}
=Z=Countable
Hence,
countable.
Case 4:If A and B are both countably infinite sets.
Suppose A=N and B=Z
Then,
=
=Z
Hence,
is countable.
Therefore, if A and B are countable sets, then
is also countable.
The point estimate would be 2.25%.
Confidence intervals are centered around a point estimate; that is, the point estimate is in the very middle of the confidence interval. We can find the point estimate by averaging both ends of the confidence interval together:
(1.1+3.4)/2 = 2.25.
Answer:
= - 2
Step-by-step explanation:
The n th term ( explicit formula ) for a geometric sequence is
= a
where a is the first term and r the common ratio
Here a = - 2 and r = 8 ÷ - 2 = - 4, thus
= - 2
Answer:
104x + 52
None of the expressions listed are equivalent to 52(2x + 1)
Step-by-step explanation:
52(2x + 1)
Apply the distributive law: a(b + c) = ab + ac
⇒ 104x + 52
Therefore, 52(2x + 1) = 104x + 52