Find the approximate volume of metal in a hollow spherical shell whose internal and external radii are 3 cm and 3.0005 cm, respectively.


Given: a hollow spherical shell with internal radii 3cm and external radii 3.0005 cm


To find: the approximate volume of the metal in the hollow spherical shell


Explanation: Let the internal and external radii of the hollow spherical shell be r and R, respectively.


So it is given,


R = 3.0005 and r = 3


And let the volume of the hollow spherical shell be V.


Then we know,



Now substituting the values of R and r, we get



Now using the differentiation to get the approximate value of (3.0005)3.


But the integer nearest to 3.0005 is 3,


So 3.0005 = 3+0.0005


So let a = 3 and h = 0.0005


Hence, (3.0005)3 = (3+0.0005)3


Let the function becomes,


f(x) = x3………(ii)


Now applying first derivative, we get


f’(x) = 2x2……….(iii)


Now let f(a+h) = (3.0005)3


Now we know,


f(a+h) = f(a)+hf’(a)


Now substituting the function from (ii) and (iii), we get


f(a+h) = a3+h(3a2)


Substituting the values of a and h, we get


f(3+0.0005) = 33+(0.0005) (3(32))


f(3.0005) = 27+(0.0005)(3(9))


(3.0005)3 = 27+(0.0005)(27)


(3.0005)3 = 27+0.0135


(3.0005)3 = 27.0135


Hence the approximate value of (3.0005)3 = 27.0135.


Now substituting this in equation (i), we get




V = 4π(0.0045)


V = 0.018π cm3


Hence the approximate volume of the metal in the hollow spherical shell is 0.018π cm3.


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