# Find two positive numbers whose product is 100 and whose sum is a minimum.

1. 👍
2. 👎
3. 👁
4. ℹ️
5. 🚩

1. S=a+b
but a= 100/b
S=100/b + b

dS/db=0=-100/b^2 +1

solve for b, then go back and solve for a.

1. 👍
2. 👎
3. ℹ️
4. 🚩
2. i hope i got it right. The two numbers are 10 and 10?

1. 👍
2. 👎
3. ℹ️
4. 🚩
3. Exactly right. It's just the same as finding a rectangle of maximum area for a given perimeter. It's always a square.

1. 👍
2. 👎
3. ℹ️
4. 🚩
4. thanks guys!

1. 👍
2. 👎
3. ℹ️
4. 🚩