1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Nesterboy [21]
2 years ago
9

I NEED HELP WITH PRECALC PLEASE

Mathematics
2 answers:
alisha [4.7K]2 years ago
8 0

Answer: First question: D, Second question: A

Step-by-step explanation:

Note: I'm not so good at expanding so I'll just solve it :)

So this leaves either C or D

Apply the sum rule:

8-70=-62

The only one that gives a negative sum is D

For the second picture, the one you have chosen is correct

a1 = 3 and r = -5 so:

an = 3/5 * (-5)^n

Plugging in 8 for n (the first choice) we get the given term: -234,375

melamori03 [73]2 years ago
5 0

Answer:

  1. (d)  2 +(-5) +(-12) +...
  2. (a)  a8

Step-by-step explanation:

<h3>1.</h3>

Putting n = 0 and n = 1 into the expression being summed will show you which series is correct.

  2 -7n for n=0 is 2 -7·0 = 2

  2 -7n for n=1 is 2 -7·1 = -5

The series of the last choice (d) is correct.

__

<h3>2.</h3>

The given sequence is exponential with a first term of 3 and a common ratio if -5. Then the n-th term is ...

  an = 3(-5)^(n -1)

We want to find n for an = -234,375.

  -234375 = 3(-5)^(n-1)

  -78125 = (-5)^(n-1)

For n to be a real number, we must have n even. In that case, the value of n is equivalent to the value that is the solution to ...

  78125 = 5^(n -1)

Taking logs of both sides, we get ...

  log(78125) = (n -1)·log(5)

  log(78125)/log(5) = n -1 . . . . . . . . . . . . divide by log(5)

  n = 1 +log(78125)/log(5) = 1 +7 = 8 . . . add 1 and evaluate

-234,375 is the 8th term of the sequence.

You might be interested in
A cone has a diameter of 7.5 ft and a height of 4.25 ft. What is the volume of the cone to the nearest tenth? Use 3.14 for π.
leva [86]

Answer:

The volume of a cone is 62.5\ \text{feet}^3.

Step-by-step explanation:

We have,

Diameter of a cone is 7.5 ft

Radius of a cone is 3.75 ft

Height of the cone is 4.25 ft

It is required to find the volume of the cone. The formula of the volume of cone is given by :

V=\dfrac{1}{3}\pi r^2 h\\\\V=\dfrac{1}{3}\times 3.14\times (3.75)^2\times 4.25\\\\V=62.55\ \text{feet}^3

So, the volume of a cone is 62.5\ \text{feet}^3.

3 0
3 years ago
A six sided number cube is laveled with number from 1 to 6 . If a student tolls the cube 150 times howany times should they expe
andrey2020 [161]

Answer:

75 times

Step-by-step explanation:

6 sided die - 1,2,3,4,5,6

3 of these numbers are even

P(even) = 3/6 = 1/2

1/2 * 150 = 75

7 0
3 years ago
A diamond today cost ten dollars more than twice what it cost last year.The sum of the cost (last year and this year) is $2500.
nadya68 [22]

Answer:

The cost of the diamond last year is x = $ 830

Step-by-step explanation:

Let the cost of diamond last year = x

the cost of diamond present year = y

Given that diamond today cost ten dollars more than twice what it cost last year.

⇒ y = 2 x + 10  ------ (1)

The sum of the cost (last year and this year) is  = $ 2500

⇒ x + y = $ 2500 -------- (2)

Put the value of y in equation (2) from equation (1), we get

⇒ 2 x + 10 + x = $ 2500

⇒ 3 x = 2490

⇒ x = $ 830

& y = 2500 - 830

⇒ y = $ 1670

Therefore the cost of the diamond last year is x = $ 830

6 0
3 years ago
A pilot took 1/2 hours to complete his 1/3 pf his ttip how much longer will it take him to complete his trip?
Norma-Jean [14]

Answer:

1.5 hours

Step-by-step explanation:

1/2 + 1/2 + 1/2 =1.5

7 0
2 years ago
How many decibels is this? show work​
slavikrds [6]

Answer:

  • <u>115 dB</u>

Explanation:

<u>1. Given equation:</u>

\beta =10log(\frac{I}{I_0})\\\\ I_0=10^{-12}W/m^2

<u>2. Given intensity:</u>

I=0.315W/m^2

<u>3. Decibels</u>

\beta =10log(0.315/10^{-12})\\ \\ \beta =10log(315,000,000,000)\\ \\ \beta =10(11.498)=114.98\approx 115

4 0
3 years ago
Other questions:
  • 8 please and thank u
    10·1 answer
  • Find the value of k if area of triangle is 4 unit and vertices are (-2,0),(0,4),(0,k)
    5·1 answer
  • What is the standard notation for the distance of 2.4x10^5 miles
    13·1 answer
  • What does -5 * -6 equal
    6·2 answers
  • Graphically, deadweight loss is shown by the: select one:
    12·1 answer
  • Simplify the expression: 2(2 + 6g)
    13·2 answers
  • Work out the value of x
    8·1 answer
  • May someone plz help me I would appreciate it
    6·1 answer
  • I need help! this question is from my iready eighth grade test and I don’t understand it!!
    5·1 answer
  • 78 is 65% of what number?
    6·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!