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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Originally Posted by camherokid 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?
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
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 right
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