Reference angle is the angle that is formed by the the terminal side of teh angle and the horizontal line or the x-axis. The reference angles of the different quadrants can be determined using the formula correspondingly:
Quadrant 1: RF = actual angle
Quadrant 2: RF = actual angle - 90 = actual angle - pi/2
Quadrant 3: RF = actual angle - 180 = actual angle - pi
Quadrant 4 : RF = actual angle - 270 = actual angle - 3/4 pi
The first thing to do is to determine the quadrants of each angle and then apply the formula:
a. 19 pi /4 = 855 deg = 2nd Q = 135 + 45 = 180 (correct)
b. 15 pi/4 = 675 deg = 4th Q = 315 + 45 = 360 (correct)
c. 7 pi/4 = 315 deg = 4th Q = 315 + 45 = 360 (correct)
d. 12 pi/4 = 540 deg = x axis = not correct
Answers are A, B and C.
Answer:
The number of liters for :
Acid solution a = x = 8 liters
Acid solution b = y = 32 liters
Step-by-step explanation:
Let us represent:
The number of liters for :
Acid solution a = x
Acid solution b = y
Suppose a chemist combines a 25% acid solution and a 50% acid solution to make 40 L of 45% acid solution.
x + y = 40 ...... Equation 1
x = 40 - y
25% × x + 50% × y = 45% × 40
0.25x + 0.5y = 18...... Equation 2
We substitute, 40 - y for x in Equation 2
0.25(40 - y)+ 0.5y = 18
10 - 0.25y + 0.5y = 18
- 0.25y + 0.5y = 18 - 10
0.25y = 8
y = 8/0.25
y = 32 Liters
Solving for x
x = 40 - y
x = 40 - 32
x = 8 Liters.
Hence:
The number of liters for :
Acid solution a = x = 8 liters
Acid solution b = y = 32 liters
Answer:
the answer is D, 8
Step-by-step explanation:
Hope this helps!❆
Answer:
The answer is below
Step-by-step explanation:
Let s(t) represent the amount of salt in the tank at time t. Therefore:
ds / dt = (rate of salt flowing into the tank) - (rate of salt going out of the tank)