Hi there!
To solve, we must use the following trig identity:
sin(u - v) = sin(u)cos(v) - sin(v)cos(u)
We can rewrite the left hand side of the equation as:

Split the fraction:

First fraction reduces to 1:

Simpify each with common arguments:

Answer:
is isosceles.
Step-by-step explanation:
Please have a look at the attached figure.
We are <u>given</u> the following things:


Let us try to find out
and
. After that we will compare them.
<u>Finding </u>
<u>:</u>
Side EG is a straight line so 
is sum of internal
and external 
<u>Finding </u>
<u>:</u>
<u>Property of external angle:</u> External angle in a triangle is equal to the sum of two opposite internal angles of a triangle.
i.e. external
= 

Comparing equations (1) and (2):
It can be clearly seen that:

The two angles of
are equal hence
is isosceles.
Which parabola?

Equation of the parabola
y - y1 = 4p(x - x1)
The Vertex of the parabola given is (0, 0) because it does not have the values of x1 and y1.
Then Vertex = (0,0)
-Look for two values of y to the left and two points to the right.
You can choose the points that you which
x y
-3 y = -(-3)^2 = -9
-1 y = -(-1)^2 = -1
0 y = -(0)^2 = 0
1 y = -(1)^2 = -1
3 y = -(3)^2 = -9
Jim is ranked third best in his class of 50 students.