3a)
`A=\sqrt{\sqrt{5}-\sqrt{3-\sqrt{29-12\sqrt{5}}}}`
`A=\sqrt{\sqrt{5}-\sqrt{3-\sqrt{(2\sqrt{5})^2-2.2\sqrt{5}.3+9}}}`
`A=\sqrt{\sqrt{5}-\sqrt{3-\sqrt{(2\sqrt{5}-3)^2}}}`
`A=\sqrt{\sqrt{5}-\sqrt{3}-2\sqrt{5}+3}`
`A=\sqrt{\sqrt{5}-\sqrt{(\sqrt{5}-1)^2}}`
`A=\sqrt{\sqrt{5}-\sqrt(5+1)=1`