What is the arc length of f(x)=((4x^5)/5) + (1/(48x^3)) - 1 f(x)=(4x55)+(148x3)1 on x in [1,2]x[1,2]?

1 Answer
Apr 4, 2016

47651/1920~=24.81847651192024.818

Explanation:

f(x)=(4x^5)/5+1/(48x^3)-1f(x)=4x55+148x31
f"'"(x)=4x^4-1/(16x^4)f'(x)=4x4116x4

L=int_a^b sqrt(1+[f"'"(x)]^2)*dxL=ba1+[f'(x)]2dx

L=int_1^2 sqrt(1+(4x^4-1/(16x^4))^2)*dxL=211+(4x4116x4)2dx
L=int_1^2 sqrt(1+16x^8-1/2+1/(256x^8))*dxL=211+16x812+1256x8dx
L=int_1^2 sqrt(16x^8+1/2+1/(256x^8))*dxL=2116x8+12+1256x8dx
L=int_1^2 sqrt((4x^4+1/(16x^4))^2)*dxL=21(4x4+116x4)2dx
L=int_1^2 (4x^4+1/(16x^4))*dxL=21(4x4+116x4)dx
L=(4/5x^5-1/(48x^3))|_1^2L=(45x5148x3)21
L=(4*32)/5-1/(48*8)-(4/5-1/48)L=43251488(45148)
L=(128-4)/5-(1-8)/384=124/5+7/384=(47616+35)/1920L=1284518384=1245+7384=47616+351920
L=47651/1920~=24.818L=47651192024.818