# It's Time To Have Pi Today

**Geometry**Level 4

\[ 4\left( \arctan\left( \dfrac { 1 }{ x } \right) + \arctan\left( \dfrac { 1 }{ { x }^{ 3 } } \right) \right) =\pi \]

Let \(x\) be the positive real number satisfying the equation above and \({x}^{3}-x\) can be expressed as

\[ \dfrac { a }{ b } \left( c+\sqrt { d } \right) \; , \]

where \(a, b, c\) and \(d\) are positive integers, with \(a,b\) coprime and \(d\) square-free.

Find the value of the expression below.

\[ 4\left( \arctan\left( \dfrac { b }{ c } \right) + \arctan\left( \dfrac { a }{ { d } } \right) \right) \]

Give your answer to 4 decimal places.

**Your answer seems reasonable.**Find out if you're right!

**That seems reasonable.**Find out if you're right!

Already have an account? Log in here.