
is a complex number that satisfies
![\begin{cases}r\cos x=-3\\[1ex]r\sin x=4\\[1ex]r=\sqrt{(-3)^2+4^2}\end{cases}](https://tex.z-dn.net/?f=%5Cbegin%7Bcases%7Dr%5Ccos%20x%3D-3%5C%5C%5B1ex%5Dr%5Csin%20x%3D4%5C%5C%5B1ex%5Dr%3D%5Csqrt%7B%28-3%29%5E2%2B4%5E2%7D%5Cend%7Bcases%7D)
The last equation immediately tells you that

.
So you have
![\begin{cases}\cos x=-\dfrac35\\[1ex]\sin x=\dfrac45\end{cases}](https://tex.z-dn.net/?f=%5Cbegin%7Bcases%7D%5Ccos%20x%3D-%5Cdfrac35%5C%5C%5B1ex%5D%5Csin%20x%3D%5Cdfrac45%5Cend%7Bcases%7D)
Dividing the second equation by the first, you end up with

Because the argument's cosine is negative and its sine is positive, you know that

. This is important to know because it's only the case that

whenever

. The inverse doesn't exist otherwise.
However, you can restrict the domain of the tangent function so that an inverse can be defined. By shifting the argument of tangent by

, we have

All this to say

So,

.
Answer:
Henry walks 7 kilometres from school to library
Step-by-step explanation:
Given:
1 unit = 1 Kilometre
To Find:
The distance between the library and the school
Solution:
The map below shows that Henry has walked from
-2 coordinate in the x axis to coordinate 5 along the same x axis
So he has walked a total of 7 units
Since we know that 1 unit = 1 Kilometre,
7 units will be
=> 7 x 1
=> 7 Kilometres
The answer is A. Statistics. Hope this helps!