Find x, y minimizing S=x+y subject to xy=192.

[so_confused]

Find the x and y to minimize S=x+y subject to the constraint that xy=192.

What does that mean and how do I start it?? Thank you!!!

 

[galactus]

Solve the constraint for, say, y. Sub it into S, differentiate, set to 0 and solve for x.

 

[so_confused]

I solve for y=s-x sub 192 for s and 0 for y to solve for y??

 

[galactus]

Please don't take this the wrong way when I say, if you are this lost you shouldn't be in calculus. Now, moving on:

Solve xy=192 for y. Hopefully you can do that. OK?. You will get y=something.

Sub that into S=x+y for y. It'll be entirely in terms of x. Differentiate, set it to 0 and solve for x. You're done.

 

[stapel]

What does that mean...?

What does which mean? You learned about solving things "subject to constraints" back in algebra, when you did linear programming. And you learning about "minimizing" with derivatives earlier in calculus.

Please reply showing all of your work so far, clearly stating where you have gotten stuck. Thank you.

Eliz.

 

[galactus]

You learned about solving things "subject to constraints" back in algebra, when you did linear programming. And you learning about "minimizing" with derivatives earlier in calculus.

You're presuming a lot here, Stapel. Appears to me to be distance learning or home schooling. 'So confused' may have the cart far ahead of the horse.

Please reply showing all of your work so far, clearly stating where you have gotten stuck. Thank you.

work so far....there doesn't appear to be any.

stating where you are stuck.....everywhere.