Answer:
Cos(2115°) =1/√2
Sin(2115°) = -1/√2
Step-by-step explanation:
We have to find the values of Cos (2115°) and Sin (2115°).
Now, 2115° can be written as (23×90°+ 45°).
Therefore, the angle 2115° lies in the 4th quadrant where Cos values are positive and Sin values are negative.
Hence, Cos (2115°) = Cos(23×90° +45°) =Sin 45° {Since 23 is an odd number, so the CosФ sign will be changed to SinФ} =1/√2 (Answer)
Again, Sin (2115°) = Sin(23×90° +45°) = -Cos 45° {Since 23 is an odd number, so the SinФ sign will be changed to CosФ} = -1/√2 (Answer)
Now, the required reference angle is 45°. (Answer)
Im pretty sure that it is the first answer
Number of weekend minutes used: x
Number of weekday minutes used: y
This month Nick was billed for 643 minutes:
(1) x+y=643
The charge for these minutes was $35.44
Telephone company charges $0.04 per minute for weekend calls (x)
and $0.08 per minute for calls made on weekdays (y)
(2) 0.04x+0.08y=35.44
We have a system of 2 equations and 2 unkowns:
(1) x+y=643
(2) 0.04x+0.08y=35.44
Using the method of substitution
Isolating x from the first equation:
(1) x+y-y=643-y
(3) x=643-y
Replacing x by 643-y in the second equation
(2) 0.04x+0.08y=35.44
0.04(643-y)+0.08y=35.44
25.72-0.04y+0.08y=35.44
0.04y+25.72=35.44
Solving for y:
0.04y+25.72-25.72=35.44-25.72
0.04y=9.72
Dividing both sides of the equation by 0.04:
0.04y/0.04=9.72/0.04
y=243
Replacing y by 243 in the equation (3)
(3) x=643-y
x=643-243
x=400
Answers:
The number of weekends minutes used was 400
The number of weekdays minutes used was 243
To find the percentage of a number, first, convert it to a decimal and then multiply.
To convert a percentage to a decimal, move the decimal point over 2 spaces to the left. That makes 80% = 0.80
Then multiply 0.80 by 30.
0.80 • 30 = 24
Peggy got 24 questions correct.
Answer:
What is a b e and f u just said // I think its supposed to be a number
Step-by-step explanation:
