S
How to find two positive x and y that minimize Q=x^2y if x+y+2 ?



This Question is Closed

Brutal
Best Response
You've already chosen the best response.
0
did u mean x+y=2?

S
Best Response
You've already chosen the best response.
2
oh, yes, sorry x+y=2

Brutal
Best Response
You've already chosen the best response.
0
x+y = 2
y = 2x
Q=(x^2)*y = x^2(2x) = 2x^2x^3
Q' = 4x  3x^2 = 0
x(43x)=0
x=0;
43x=0, 3x=4; x=4/3

cshalvey
Best Response
You've already chosen the best response.
1
@S did you leave? Because it looks like @Brutal was putting in some time to help you here...

S
Best Response
You've already chosen the best response.
2
no , i am steel here, just trying to understand this

S
Best Response
You've already chosen the best response.
2
still*

cshalvey
Best Response
You've already chosen the best response.
1
Cool, no worries then  as you were ;)

Brutal
Best Response
You've already chosen the best response.
0
okay just keep the positive positive value: x=4/3
x=4/3, but you know that y = 2 x, so y = 2(4/3) = (64)/3 = 2/3

S
Best Response
You've already chosen the best response.
2
yes, was just thinking about y value =D, thank you soo much for your help!

cshalvey
Best Response
You've already chosen the best response.
1
Great job both of you @S and @Brutal. Thank you from OpenStudy!

Brutal
Best Response
You've already chosen the best response.
0
np :)