What Are Some Suggestions for Checking an Answer and Identifying Mistakes?

[kingboy]

can you help me to check the answer ?pls give some suggestion ...i think someway is wrong...

 

[tiny-tim]

hi kingboy!

you've included the area of the top surface of the cylinder

 

[kingboy]

hi kingboy!

you've included the area of the top surface of the cylinder

so that mean the total surface area need to -$$\pi$$r^2(top circle)?
how about the method ? is that correct? because late need to dy/dx...

can someone help to correct or circle the wrong part?pls ...

 

[tiny-tim]

hi kingboy!

how about the method ? is that correct?

i don't understand how you got equation circle-2 …

you need to take the equations for A and V and to prove that A = 2V/r + 5πr²/3

 

[chiro]

so that mean the total surface area need to -$$\pi$$r^2(top circle)?
how about the method ? is that correct? because late need to dy/dx...

can someone help to correct or circle the wrong part?pls ...

Like tiny-tim pointed out you are including an extra circle. Think of your cylinder as having the top opened. Instead of that circle, you have your hemisphere on the top and not a flat circle.

 

[kingboy]

o i know where i make mistake thank for helping ...