Answer:

Step-by-step explanation:
We have to simplify the trigonometric expression 
Let us multiply the numerator and denominator by 

In the denominator apply the formula for difference of squares

Thus, the denominator will become

Thus, the expression is

Using the relation 

We can rewrite this expression as

Finally, the simplified expression is

Answer:
b
Step-by-step explanation:
Answer:
Step-by-step explanation: For example, if we have matrix A whose all elements in the first column are zero. Then, by one of the property of determinants, we can say that its determinant is equal to zero. Hence, A would be called as singular matrix. Note that singular matrices are non-invertible (their inverse does not exist).
X = 23
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