The product of two positive numbers is 1024. What is the minimum value of their sum?
Solution:
Let the first positive number be x.
Let the second positive number be y.
The product of two positive numbers = 1024
x.y = 1024 --- (1)
We have to find the minimum value of the sum.
Sum, S = x + y --- (2)
From (1), y = 1024/x
So, S = x + (1024/x)
Differentiating both sides with respect to x and equating to zero, to find the minimum value of the sum.
dS/dx = 1 - 1024/x2 = 0
1 - 1024/x2 = 0
1 = 1024/x2
x2 = 1024
Taking square root,
x = ±32
Since, the number is positive.
Take x = +32.
Now, y = 1024/32
y = 32
The numbers are 32, 32.
Sum = 32 + 32
Sum = 64
Therefore, the minimum value of their sum is 64.
The product of two positive numbers is 1024. What is the minimum value of their sum?
Summary:
The product of two positive numbers is 1024. The minimum value of their sum is 64.
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