Use differential to estimate the amount of paint needed to apply a coat of paint 0.05cm thick to a hemispherical dome with diameter 50cm.
S= 2 pi r^2
ds= 4 pi r dr.
r= 50/2= 25 cm
dr= 0.05cm
So ds= 4 pi 25*0.05= 5 pi cm^2
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Use differential to estimate the amount of paint needed to apply a coat of paint 0.05cm thick to a hemispherical dome with diameter 50cm.
S= 2 pi r^2
ds= 4 pi r dr.
r= 50/2= 25 cm
dr= 0.05cm
So ds= 4 pi 25*0.05= 5 pi cm^2
i may be wrong, but isn't the amount of paint talking about volume?Quote:
Originally Posted by camherokid
So the answer must be this :
V= 2/3* pi r^3
dV= 2 pi r^2 dr.
r= 50/2= 25 cm
dr= 0.05cm
So dV= 2 pi 25^2*0.05= 62.5 pi cm^3
yup, that looks about rightQuote:
Originally Posted by camherokid