Deflection	$X_1\left(x\right)=w\left(x\right);$
Angle of rotation	$X_2\left(x\right)=\varphi \left(x\right);$
Bending moment	$X_3\left(x\right)=M\left(x\right);$
Transverse shear force	$X_4\left(x\right)=Q\left(x\right);$
Beam height	$X_5\left(x\right)=h\left(x\right);$
Derivative of the beam height distribution	$X_6\left(x\right)={\displaystyle \frac{\mathrm{d}h}{\mathrm{d}x}}.$