Express the complex number in trigonometric form.
1 answer:
-5i can be written as 0 + (-5)i
It is in the form a+bi where a = 0 and b =-5
So the point (a,b) is (0,-5)
The distance from the origin to this point is 5 units, therefore r = 5. This is the magnitude.
The angle is 270 degrees as shown in the attached image. You start on the positive x axis and rotate until you reach the point (0,-5)
This is why the answer is choice A) 5(cos(270) + i*sin(270))
It is in the form a+bi where a = 0 and b =-5
So the point (a,b) is (0,-5)
The distance from the origin to this point is 5 units, therefore r = 5. This is the magnitude.
The angle is 270 degrees as shown in the attached image. You start on the positive x axis and rotate until you reach the point (0,-5)
This is why the answer is choice A) 5(cos(270) + i*sin(270))
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Answer:
59 to 66
Step-by-step explanation:
Mean test scores = u = 74.2
Standard Deviation = = 9.6
According to the given data, following is the range of grades:
Grade A: 85% to 100%
Grade B: 55% to 85%
Grade C: 19% to 55%
Grade D: 6% to 19%
Grade F: 0% to 6%
So, the grade D will be given to the students from 6% to 19% scores. We can convert these percentages to numerical limits using the z scores. First we need to to identify the corresponding z scores of these limits.
6% to 19% in decimal form would be 0.06 to 0.19. Corresponding z score for 0.06 is -1.56 and that for 0.19 is -0.88 (From the z table)
The formula for z score is:
For z = -1.56, we get:
For z = -0.88, we get:
Therefore, a numerical limits for a D grade would be from 59 to 66 (rounded to nearest whole numbers)