The cross section of the reflector in a flashlight is a parabola. suppose the light bulb is located at the focus of the cross section, 2 cm in front of the vertex.

assume the vertex is at the origin and that the parabola is concave left (it opens left as depicted in the picture). what is the equation for the cross section of the reflector

Correct  y² = - 8 x

Step-by-step explanation:

The equation of the parabola turned to the left ie to the negative side of the coordinate system is:

y² = - 2 p x  where p is the parameter of the parabola

The relationship between the parameter and the focus is.

p = 2 f   => p = 2 · 2 = 4 cm  

then the equation of the parabola is:

y² = - 2 p x = - 2 · 4 x = - 8 x

y² = - 8 x

God is with you!!!

not only in mathematics, scientific proof also are required in the other field of science. also maths proofs are of particular structure, containing steps and logics. so proving is like doing science, it is science. that's why it is important to prove. 

an inaccurate proof leads to errors, or stating results that are not accurate.  which wil mess the probelm up you dont want this

b.-4 units

all you   do is count how many times you move