Answer and Step-by-step explanation: Spherical coordinate describes a location of a point in space: one distance (ρ) and two angles (Ф,θ).To transform cartesian coordinates into spherical coordinates:


For angle θ:
- If x > 0 and y > 0:
;
- If x < 0:
; - If x > 0 and y < 0:
;
Calculating:
a) (4,2,-4)
= 6
For θ, choose 1st option:
b) (0,8,15)
= 17


The angle θ gives a tangent that doesn't exist. Analysing table of sine, cosine and tangent: θ = 
c) (√2,1,1)
= 2

= 

d) (−2√3,−2,3)
= 5

Since x < 0, use 2nd option:



Cilindrical coordinate describes a 3 dimension space: 2 distances (r and z) and 1 angle (θ). To express cartesian coordinates into cilindrical:

Angle θ is the same as spherical coordinate;
z = z
Calculating:
a) (4,2,-4)
= 

z = -4
b) (0, 8, 15)
= 8

z = 15
c) (√2,1,1)
= 

z = 1
d) (−2√3,−2,3)
= 4

z = 3
Answer: 113.04
Step-by-step explanation: The equation for the area of a circle is pi r squared so you have to find the radius first. To find the radius, find the diameter first. A way to do this which was easiest for me was dividing 37.68 by pi (3.14), which is 12. Divide the diameter by 2 to find the radius, 6.
Now use the equation from the beginning, pi r squared. So plug in pi as 3.14, then the radius as 6. It is important to always square the radius first, which would be 36. Now multiply 36 by 3.14, and there should be your answer.
Answer:
y=4, x=8
Step-by-step explanation:
system:
x+y = 12, x=2y
convert to 1 variable, simplify:
2y+y=12
3y=12
y=4
x=2y=4*2=8