https://static.k12.com/nextgen_media/assets/8078625-NG_AL1_J_03_U06_Quiz_15.png The graph shows the maximum height, in inches, reached by a pendulum on each swing. On what swing did the pendulum's maximum height dip below 1 in. for the first time? A. the 3rd swing B. the 4th swing C. the 5th swing D. the 6th swing
@Vocaloid
select the first x-coordinate where the matching y-coordinate is less than 1
C
you're getting closer but there's one x-coordinate less than 5 that has as y-coordinate less than 1
ok i worked it out it's either B or D because A is out of the question and C
so since i checked the graph, it's D
|dw:1511976606639:dw|
|dw:1511976611849:dw|
oh B
good
https://static.k12.com/nextgen_media/assets/8078569-NG_AL1_J_03_U06_Quiz_01.png The graph shows a car's value as a function of its age. Select from the drop-down menus to correctly describe the graph. The graph shows exponential __________. decay or growth As the value of the car decreases, time ____________. increases or decreases
is the value of the car going up or down as the age increases?
UP
|dw:1511976835055:dw|
no down
|dw:1511976840214:dw|
good so it should be decay and decreases
https://static.k12.com/nextgen_media/assets/8078622-NG_AL1_J_03_U06_Quiz_06.png The points on the curve represent the number of teams remaining in a tournament as a function of the number of games that have been played. What is the number of teams who began the tournament? Enter your answer in the box. __________
hint: what is the number of teams when games played = 0
8
remember that games played is on the x-axis |dw:1511977000394:dw|
|dw:1511977008852:dw|
4
each coordinate is (games played, teams remaining) so what is the y-value when x = 0?
4
|dw:1511977132086:dw|
64
good, (0,64) means 64 games at the start so 64 = your answer
https://static.k12.com/nextgen_media/assets/8078571-NG_AL1_J_03_U06_Quiz_07.png The graph shows the processing speeds of computers as a function of time since 1980. Which statements are true about the function? Select each correct answer. The practical domain is x > 0 , so the processing speed increases over time. The graph is ascending, indicating that the processing speed increases over time. The practical range is y ≥ 16 , so the processing speeds are always positive. The point (0, 16) represents an initial processing speed of 16 MHz. The point (10, 256) represents the maximum processing speed.
well first off is the graph increasing or decreasing?
decreasing
|dw:1511977304644:dw|
|dw:1511977309868:dw|
increasing
good since 0 is included in the domain, statement 1 is actually false since x > 0 excludes 0 from the domain
statement 2 we said was true (increasing graph)
for statement 3, the minimum y-value is 16 so statement 3 is true
1st one right and 2
wrong
statement 4 is true since this represents the speed when x = 0
statement 5 is false because the graph has no maximum (notice how the graph increases past (10,216)
https://static.k12.com/nextgen_media/assets/8078624-NG_AL1_J_03_U06_Quiz_12.png After being dropped from a platform, a ball bounces several times. The graph shows the height of the ball after each bounce. What does the end behavior for x increasing without bound represent? A. The height of the platform is unknown. B. The ball will never stop bouncing. C. The end behavior for x decreasing without bound is meaningless in this situation. D. The height of each bounce will approach 0 m.
as a hint, notice how the height gets closer and closer to 0 as the # of bounces increase
which answer choice matches this statement?
B
key phrase: "height gets closer to 0"
D
good, d
What is the recursive rule for an = 4n − 1? A. a1 = 4;an = an−1 − 1 B. a1 = 3; an = an−1+ 4 C. a1= −1; an = an− 1 + 4 D. a1 = 3; an = an −1 −1
first step is to calculate a1 using n = 1 when n = 1, what does 4n - 1 equal?
3
good, now calculate 4n - 1 when n = 2
7
good, and if you continue this pattern, the term increases by 4 each time making B the only answer that matches the initial term and rate of change
Haylee opened her savings account with $440 in Week 1. Each week after this, she deposited $65 in her account. How much money will Haylee have in her savings account after Week 25? Enter your answer in the box. $__________
general formula for sequences an = a1 + (n-1)d a1 = first term d = common difference n = number of terms
in this case, 440 is the first term, d is the rate of increase (65)
so our formula becomes an = 440 + (n-1)*65 let n = 25 and find an
5 • (13n + 75)
440 + (n-1)*65 replace "n" with "25" and calculate this
2000
good that's it.
What is the 8th term in the sequence? an = 25 − 3n Enter your answer in the box. ___________
my answer is 1
good that's it.
What is the explicit rule for the sequence? 15.5,13,10.5,8,5.5,3,... A. an=18 − 2.5n B. an=15.5 + 2.5n C. an=15.5 − 2.5n D. an=18 + 2.5n
MY ANSWER IS A
nvm that's right
What is the common difference, d, of the sequence? −92, −74, −56, −38, −20, ... Enter your answer in the box. d = _____
my answer is 18
good
What is the value of a3 in the sequence? 2,5,10,17,... A. 2 B. 5 C. 10 D. 17
MY ANSWER IS D
a3 means the third term
counting from the left, the third term is 10
really are you sure?
Which answer describes the type of sequence? 99,89.9,78.8,68.7,... A. geometric B. neither arithmetic nor geometric C. arithmetic
my answer is B
good.
Which answer describes the type of sequence? 1,6,7,13,... A. arithmetic B. neither arithmetic nor geometric C. geometric
is there a common difference or a common ratio?
common ratio
is 13/7 equal to 7/6?
no
good so there must be no common ratio making the sequence not geometric and not arithmetic
so B
Which answer describes the type of sequence? 3,4,5,6,... A. arithmetic B. neither arithmetic nor geometric C. geometric
is there a common difference or ratio?
common difference
good so arithmetic (A)
What is the value of a1 in the sequence? −4,−2,− 1/2,− 1/4,... A. −1/4 B. −1/2 C. −4 D. −2
what's the first number in the sequence?
C
good
What is the explicit rule for this geometric sequence? 2/9, 2/3, 2, 6,... A. an = 3(2/9)^n B. an = 3(29)^n−1 C. an = 2/9 ⋅ 3^n D. an = 2/9 ⋅ 3^n−1
|dw:1511979407260:dw|
in this case your first term is (2/9) and the common ratio is 3
substitute these values into the formula and pick the answer that matches
the answer is B and C
there is only one correct answer
|dw:1511979564396:dw|
a = (2/9) and r = 3 which answer choice matches the correct formula?
D
good.
What is the recursive rule for this geometric sequence? 3, 3/2, 3/4, 3/8,... A. a1 = 3; an =1/2 ⋅ an−1 B. a1 = 3/2;an = 1/2 ⋅ an−1 C. a1 = 1/2; an = 3/2 ⋅ an−1 D. a1 = 1/2; an = 3 ⋅ an−1
the first term (a1) is 3 so there is only one answer choice that matches
A
good
What is the explicit rule for this geometric sequence? a1 = 4; an = 1/3 ⋅ an−1 A. an = 1/3 ⋅ 4n B. an = 1/3 ⋅ 4n−1 C. an = 4(1/3)n−1 D. an = 4(1/3)n
first term is 4, common ratio is (1/3) so using the formula from earlier find the explicit formula
|dw:1511980010410:dw|
B
hint: the common ratio is the part that gets raised to the n - 1power
the first term is on the left of the formula
D
the exponent is n - 1 not just n
c
good, c.
use the geometric formula where first term = 100 and common ratio = 11/2, for n = 5
A company earns a profit of $100 the first month it is in business. Every month after that, the company earns a profit that is 1 1/2 times the previous month's profit. What will the company's profit be in the fifth month?
sorry typ
my answer is $506.25
good.
What is the common ratio for the geometric sequence? 54,36,24,16... Enter your answer in the box. ___________
just divide the 2nd term by the first term
36/54 and reduce to the lowest terms
2 — = 0.66667 3
good, if you can enter it as 2/3 I would recommend that otherwise I guess you could round to 0.6667 or whatever
the answer is 3/2
correct ?
it is 2/3
What is the recursive rule for this geometric sequence? 7, 21, 63, 189, … A. a1 = 7; an = 3 ⋅ an−1 B. a1 = 3; an = 7 ⋅ an−1 C. a1 = 7;an = 1/3 ⋅ an−1 D. a1 = 21;an= 7 ⋅ an−1
hint - what's the common ratio? what's the first term?
7
good, first term is 7 and what is the common ratio?
21
to find the common ratio divide the 2nd term by the 1st term
21/7 = ?
3
3
3
good, so pick the answer choice where a1 = first term = 7 and an = common ratio * a^(n-1)
D
a1 must be 7 not 21.
C
the common ratio is 3 not 1/3
A
good.
can we close this and open a new question, it's getting laggy
YES
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