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3. What is the focus of the parabola?

y=−14x2−x+3

Enter your answer in the boxes.

(__,__)

 

4. The equation of a parabola is y=12x2+6x+23 .

What is the equation of the directrix?

 

y = 5.5

y = 4.5

​y = 2​

​y = 0.5

 

5. The equation of a parabola is 132(y−2)2=x−1 .

What are the coordinates of the focus?

(1, 10)

(1, −6)

(9, 2)

(−7, 2)

 May 11, 2018
 #1
avatar+118696 
+1

Please post one question at a time.

 

3. What is the focus of the parabola?

y=−14x2−x+3

Enter your answer in the boxes.

 

y=14x2x+3y3=14(x2+114x)114(y3)=x2+114x114(y3)+1784=x2+114x+1784114(y3156)=(x+128)2(x+128)2=114(y3156)(x+128)2=4156(y3156)

 

concave down parabola

 

Vertex=(128,3156)Axisofsymmetry:x=128focallength=156focus=(128,3156156)focus=(128,3)

 

Here is the graph

 

 May 11, 2018
 #2
avatar+118696 
+1

The others must be done by rearranging the equations as well.

 

you need them of the form

 

(xh)2=4a(yk)

 

Where (h,k) is the vertex and |a| is the focal length.

 May 11, 2018
 #3
avatar+118696 
+1

The last one is sideways so the x and y will be swapped around.

 May 11, 2018

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