Factor:
2sin^2x-sinx = 0
sinx(2sinx - 1) = 0
Therefore the solutions are when:
sin x = 0
And
sinx = 1/2
So sinx = 0
is true when x = 0 and pi and all the angles coterminal with these points. Thus, the answer is x = pi*n, (where n is some integer)
sinx = 1/2
is true when x = pi/6 and 5pi/6 and the angles coterminal with these points.
Thus, the answer is x = pi/6 + 2pi*n (where n is some integer)
and x = 5pi/6 + 2pi*n (where n is some integer)
The sum of the first 20 terms of an arithmetic sequence with the 18th term of 8.1 and a common difference of 0.25 is 124.5
Given,
18th term of an arithmetic sequence = 8.1
Common difference = d = 0.25.
<h3>What is an arithmetic sequence?</h3>
The sequence in which the difference between the consecutive term is constant.
The nth term is denoted by:
a_n = a + ( n - 1 ) d
The sum of an arithmetic sequence:
S_n = n/2 [ 2a + ( n - 1 ) d ]
Find the 18th term of the sequence.
18th term = 8.1
d = 0.25
8.1 = a + ( 18 - 1 ) 0.25
8.1 = a + 17 x 0.25
8.1 = a + 4.25
a = 8.1 - 4.25
a = 3.85
Find the sum of 20 terms.
S_20 = 20 / 2 [ 2 x 3.85 + ( 20 - 1 ) 0.25 ]
= 10 [ 7.7 + 19 x 0.25 ]
= 10 [ 7.7 + 4.75 ]
= 10 x 12.45
= 124.5
Thus the sum of the first 20 terms of an arithmetic sequence with the 18th term of 8.1 and a common difference of 0.25 is 124.5
Learn more about arithmetic sequence here:
brainly.com/question/25749583
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We find the length of AD using the similarity of right triangle property. See image attached.
AD² = BD × CD
AD² = 9 × 36
AD² = 324
AD² = 18²
AD = 18
The length of AD is 18 units
Answer:
y=2x+8
Step-by-step explanation:
All of the choices are in slope-intercept, or y=mx+b form where m is the slope and b is the y intercept. Therefore if the slope is 2, and the y intercept is 8 the equation should be y=2x+8.
Answer:
80 adults must addent to make a complete $1,000
Step-by-step explanation:
You start with the students, $3 for each and 200 of them attend. 3x200=600 dollars in total. Then you would subtract 600 from 1,000. Next you will do the adults, 5x80=400 (The "leftover" cash) $5 for each times 80 adults will be $400 in total.
