Let P be the plane that intersects
- x-axis at point (-5,0,0);
- y-axis at point (0,-2,0);
- z-axis at point (0,0,5).
Write the equation of the plane P:

Then

The coefficients at variables x, y and z are the coordinates of perpendicular vector to the plane. Thus

Answer: 
Answer:
.
Reference angle is 
Step-by-step explanation:
Given the value of x. we have to find the correct value of cosx.

Now, we have to find the exact value of 



Now, we have to find the reference angle of
.
Since the angle
lies in second quadrant, the reference angle formula is
Reference angle=
.
=
Answer:
See the proof below.
Step-by-step explanation:
For this case we need to proof the following indentity:

So we need to begin with the definition of tangent, we know that
and we can do this:
(1)
We also have the following identities:


Now we can apply those identities into equation (1) like this:
(2)
We can divide numerator and denominator from expression (2) by
we got this:

And simplifying we got:

And that complete the proof.
Answer:
It is a function Jonny!
Step-by-step explanation:
Hello! I would say to Jonny:
Jonny! A function is a relation between two sets, in which every element of the first set (domain) is assigned only one element of the second set (codomain).
If you have serveral elements of the first set with the same corresponding element of the second set it is correct to call that relation a function.
However, if you have an element of the first set for which your relation can relate to more than one element of the second set, then Jonny, that is not a function.
In the present case, every student ID number can only be realted to a number of the set {9, 10, 11, 12}, a student cannot have more than one current grade level. Therefore, that relation is in fact a function