Ask Singapore Homework?

Upload a photo of a Singapore homework and someone will email you the solution for free.



Question

secondary 4 | A Maths
One Answer Below

Anyone can contribute an answer, even non-tutors.

Answer This Question
Ethan Ow Yong
Ethan Ow Yong

secondary 4 chevron_right A Maths

I nid help wif part 3. Especially the differentiating part

Date Posted: 6 years ago
Views: 280

See 1 Answer

done {{ upvoteCount }} Upvotes
clear {{ downvoteCount * -1 }} Downvotes
Tham KY
Tham Ky's answer
6052 answers (Tutor Details)
1st
...
Ethan Ow Yong
Ethan Ow Yong
6 years ago
How do u get the 4πr tho
Tham KY
Tham KY
6 years ago
Second derivative... Do differentiation on dV/dr to get the second derivative, you will get -4(pi)r...
Ethan Ow Yong
Ethan Ow Yong
6 years ago
Oh ok. To find whether isit more than 0, u juz sub any value to r right. Or must be a specific value?
Tham KY
Tham KY
6 years ago
Must sub the r wanted, not any value.
I did not sub in this case because since the r wanted is positive r (radius cannot be negative), -4(pi)r is definitely negative since pi is a positive constant.
You may sub the r and show the second derivative is less than zero, else must state the statement.