`A=[sqrt(3)]/4*(5x-1)^2=>`

`A'=[sqrt(3)]/4*2*(5x-1)*5=>`

`A'=[5sqrt(3)]/2*(5x-1)`

`A'(1)=[5sqrt(3)]/2*(5-1)=>`

` ` `A'(1)=10sqrt(3)`

`A=[sqrt(3)]/4*(5x-1)^2=>`

`A'=[sqrt(3)]/4*2*(5x-1)*5=>`

`A'=[5sqrt(3)]/2*(5x-1)`

`A'(1)=[5sqrt(3)]/2*(5-1)=>`

` ` `A'(1)=10sqrt(3)`