Adding all the marks and dividing them by the total no. of students to get the average marks.
Avg. marks = (7+8+7+9+6)/5
Avg. marks = 37/5
Avg. marks = 7.4
= (5 - 9i) + (-4 + 7i) - (14 - 3i)
Combine like terms; two negatives make a positive when you remove parentheses
= (5 + -4 + -14) + (-9i + 7i + 3i)
= -13 + 1i or -13 + i
ANSWER: -13 + i (first choice)
Hope this helps! :)
Answer:
- height: 48.6 ft
- time in air: 3.4 s
Step-by-step explanation:
A graphing calculator provides a nice answer for these questions. It shows the maximum height is 48.6 feet, and the time in air is 3.4 seconds.
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The equation can be rewritten to vertex form to find the maximum height.
h(t) = -16(t^2 -54/16t) +3 . . . . . group t-terms
h(t) = -16(t^2 -54/16t +(27/16)^2) + 3 + 27^2/16
h(t) = -16(t -27/16)^2 +48 9/16
The maximum height is 48 9/16 feet, about 48.6 feet.
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The air time is found at the value of t that makes h(t) = 0.
0 = -16(t -27/16)^2 +48 9/16
(-48 9/16)/(-16) = (t -27/16)^2 . . . . . . . subtract 48 9/16 and divide by -16
(√777 +27)/16 = t ≈ 3.4297 . . . . . square root and add 27/16
The time in air is about 3.4 seconds.
Remark
What this is trying to tell you is that you have two factors. Each in turn can be zero, but they cannot be zero at the same time. You will get that kind of question, just not now.
So either - n = 0 or 5n - 4 =0
Solution
- n = 0 Multiply both sides by - 1
(-1)*(-n) = 0*-1
n = 0
5n - 4 = 0 Add 4 to both sides.
5n = 4 Divide by 5
n = 4/5
Comment
B and D are both wrong 4/5 is positive. and those list n as -4/5 which is wrong.
A is wrong because the function will not go to 0 if n = -1
Answer
C <<<<Answer
Answer:
see below
Step-by-step explanation:
The ratio of terms that are two terms apart (s4 and s6) is the square of the common ratio:
s6/s4 = r^2
r = √(8/18)
r = 2/3 . . . . . matches choices A and C
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Using the formula for the general term, we now know enough to find the first term:
sn = s1·r^(n-1)
s4 = s1·(2/3)^(4-1)
Using s4 = 18 and multiplying by (2/3)^-3, we get ...
18·(2/3)^-3 = s1 = 18·27/8
s1 = 243/4 . . . . . matches choice A