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
juin [17]
3 years ago
15

I need help with this, please. Any advice would be appreciated.

Mathematics
1 answer:
mote1985 [20]3 years ago
8 0

Answer:

see explanation

Step-by-step explanation:

The sum to n terms of an arithmetic sequence is

S_{n} = \frac{n}{2} [ 2a₁ + (n - 1)d ]

where a₁ is the initial value and d the common difference

Given

S_{n} = \frac{n}{2} [ 10 + (n - 1)3 ]

Then by comparison

2a₁ = 10 ( divide both sides by 2 )

a₁ = 4 ← initial value

and d = 3 ← common difference

Thus

S_{8} = \frac{8}{2} [ 10 + (7 × 3) ]

   = 4(10 + 21)

   = 4 × 31

   = 124

You might be interested in
1. A sine function has the following key features:
andrew11 [14]
Problem 1

See the attached image (figure 1)

16pi seems like a typo. I'm going to assume that it's a fraction and it is 1/(6pi)
f = 1/(6pi) = frequency
T = 1/f = 1/(1/(6pi)) = 6pi
Amplitude = 2
a = 2
b = 2pi/T = 2pi/(6pi) = 1/3
Midline: y = 3
d = 3

The function is
y = a*sin(bx-c)+d
y = 2*sin(1/3*x-0)+3
y = 2*sin(x/3)+3

===============================================

Problem 2

See the attached image (figure 2) 

T = 12 is the period
a = 4 is the amplitude
b = 2pi/T = 2pi/12 = pi/6
y = 1 is the midline so d = 1
The y intercept is (0,1) which is the midline, which indicates no phase shifts have occurred so c = 0

The function is
y = a*sin(bx-c)+d
y = 4*sin((pi/6)x-0)+1
y = 4*sin((pi/6)x)+1

===============================================

Problem 3

See the attached image (figure 3)

Period = 4pi
T = 4pi
b = 2pi/T = 2pi/(4pi) = 1/2 = 0.5
Amplitude = 2
a = 2
Midline: y = 3
d = 3
y-intercept: (0,3)
The function is a reflection of its parent function over the x-axis, so 'a' is negative meaning a = -2 instead of a = 2

The function is
y = a*sin(bx-c)+d
y = -2*sin(0.5x-0)+3
y = -2*sin(0.5x)+3

===============================================

Problem 4

See the attached image (figure 4)

a = 10 which is half of the distance between the highest and lowest points
T = 8 is the period
b = 2pi/T = 2pi/8 = pi/4
c = -pi/2 is the phase shift since its really a cosine graph
d = 0 is the midline

The function is
y = a*sin(bx-c)+d
y = 10*sin((pi/4)*x+(-pi/2))+0
y = 10*sin((pi/4)*x+pi/2)

===============================================

Problem 5

See the attached image (figure 5)

a = 2 is the amplitude since it bobs up and down this distance from the midline
T = 8 seconds is the period (double that of the time it takes for it to go from the highest to the lowest point)
b = 2pi/T = 2pi/8 = pi/4
c = 0 is the phase shift as the buoy starts at normal depth of 20 meters
d = 20 is the midline

The function is
y = a*sin(bx-c)+d
y = 2*sin((pi/4)x-0)+20
y = 2*sin((pi/4)x)+20

===============================================

8 0
3 years ago
Read 2 more answers
A dealer gains 16% by selling a mop for rs.78300.but due to competition in the market, he decides to make a profit of only 10%.
vesna_86 [32]

Answer:

The correct answer is -  72,349.2

Step-by-step explanation:

Given:

selling price = 7234.92

Initial profit = 16%

we know:

selling price = cost price + profit

Solution:

78300 = cp + 16*cp/100

profit = 78300*16/100 = 12528

cost price = 78300 - 12528 = 65772

then the profit on 10%

= 65772*10/100

= 6577.2

the new selling price = 65772+6577.2

= 72,349.2

3 0
3 years ago
Evaluate the expression n ÷ 5 for n = 3.2.<br><br> A. 0.064<br> B. 0.604<br> C. 0.64<br> D. 6.4
Licemer1 [7]

Answer:

n/5

substitution for n = 3.2

3.2/5

0.64

3 0
2 years ago
Michelle bought two blouses for $18.20 each. If she received a 10% discount for the blouses and the sales tax rate is 7.25%, how
Gnesinka [82]
The answer is B. $17.57
3 0
3 years ago
Proportions and equations solve
kirza4 [7]
Y=9x because if you divided y by x all the numbers will  equal to 9 which is proportional
7 0
3 years ago
Other questions:
  • How do you write 36.4 in word form
    13·2 answers
  • -2√7 rational or irrational?
    8·2 answers
  • He equation 2x + 8 = 2(x + 5) has
    13·1 answer
  • Which of the following represents fifth root of x squared in exponential form? x to the 2 fifths power x to the 5 over 2 power 5
    12·1 answer
  • What is the solution set of {x | x &lt; -3} ∩ {x | x &gt; 5}?
    8·1 answer
  • Mr. De Leon's Geometry class has 34 students. After lunch everyone returns to the classroom. Within an hour, each person produce
    11·1 answer
  • The equation d=60t gives the distance d (in miles) a car travels after t hours. Identify the independent and dependent variables
    8·2 answers
  • Find the surface area of the following triangular prisms
    13·1 answer
  • Dustin's town voted on a new speed limit. 40% of the 60 votes were in favor of the new speed limit. How many votes were in favor
    10·2 answers
  • Orlando bought a new couch for 1728 using electronic store Fiancé plan he will pay $96
    12·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!