Question

hlo friends..


if v is the volume and s is the surface are cubiod of dimensions a,b,c then prove that 1/v=2/5(1/a+1/b+1/c)

please fast ,it's urgent

Answer 1

a , b , c are dimensions of the

cuboid.

S = 2 ( ab + bc + ca )

V = abc

RHS = 2/S(1/a + 1/b + 1/c )

= 2/[ 2( ab+bc+ca )] { 1/a+ 1/b + 1/c}

= 1/( ab+ bc +ca ) {( bc + ac + ab )/abc }

= 1/abc

= 1/V

= LHS



Hope it may helps you