Let x and y be nonnegative real numbers. if x^2+5y^2=30, what is the max value of x + y?
x^2 + 5y^2 = 30
Take the derivative with respect to x and set to 0
2x = 0
Take the derivative with respect ot y and set to 0
10y = 0
This implies that
2x =10y
x = 5y
So
(5y)^2 + 5y^2 =30
30y^2 = 30
y = 1
x = 5y = 5
Mav x + y = 6
+1439 
