When is the point parallel to the the line?

G

Guest

Guest
How do you do this question,: At what point is the tangent to the curve x+y^2=1 parallel to the line x+2y=0?

Thanks for the help
 
This one works just like the other tangent-line question you posted. Follow the same procedure.

(Actually, this one is easier, since you're not bothering with finding the perpendicular slope.)

If you get stuck, please reply showing all the steps you have tried. Thank you.

Eliz.
 
Are we forgetting our algebra?

x+2y=0
y = -½x
Slope = -½

x + y^2 = 1
1 + 2y(dy/dx) = 0
dy/dx = -1/(2*y)

Now what?
 
do you just use common sense to find y? or is there an actualy formula? like dy/dx=-1/2y must equal -1/2 so y has to be 1. And I have trouble with these questions cuz I don't know which equation you have to find the derivative of and which one you don't need to find the derivative of
 
Are you not familiar with implicit differentiation?

Eliz.
 
bittersweet said:
I am.
Click to expand...
Great. Use that. Differentiate implicitly with respect to "x", and then solve the resulting equation for "(dy/dx)=". Set the derivative formula equal to the desired slope (just like in the previous exercise), and solve.

If you get stuck, please reply showing your work. Thank you.

Eliz.
 
Then you use algebra.

Slope = -½
dy/dx = -1/(2*y)

-½ = -1/(2*y) and solve away.
 
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