Answer:
see explanation
Step-by-step explanation:
Using the trigonometric identity
sin²x + cos²x = 1 , then
sin²x = 1 - cos²x and cos²x = 1 - sin²x
Consider the left side
← expand numerator/denominator using FOIL
=
= 
= 
= 
= cot²A = right side , thus proven
Answer:
the second option and x=20
Answer:
The percentage of students who scored below 620 is 93.32%.
Step-by-step explanation:
Problems of normally distributed samples are solved using the z-score formula.
In a set with mean
and standard deviation
, the zscore of a measure X is given by:

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
In this question, we have that:

Percentage of students who scored below 620:
This is the pvalue of Z when X = 620. So



has a pvalue of 0.9332
The percentage of students who scored below 620 is 93.32%.
So I'll walk through the first 2. Then please try the other ones and let me know if you run into more problems.
5m-6
If m is equal to 7, then replace m with 7.
5(7)-6
5x7=35 so the expression is now 35-6. Solve.
35-6=29
So that was the first one.
4m+t
We just do what we do with the first problem.
4(7)+(2)
4x7=28 so the expression is 28+2.
28+2=28
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hope it helps
p.s. When there is subtraction, add. When there is division, multiply to cancel that out. When there is multiplication, divide to cancel. etc.