Question 1137748
(Some help only)


A = 2πr^2 + 2πrh

{{{2pi*r^2+2pi*rh-A=0}}}


{{{h=4}}}{{{given}}}:


{{{2pi*r^2+8pi*r-A=0}}}

{{{r=(-8pi+- sqrt(64pi^2+4*2*A))/4}}}

{{{r=(-8pi+- 2*sqrt(64pi^2+2A)/4}}}

{{{r=(-4pi+- sqrt(64pi^2+2A))/2}}}
but not yet finished.
Needed restrictions are  {{{64pi^2+2A>=0}}}, and {{{sqrt(64pi^2+2A)>4pi}}}

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