1<math xmlns="http://www.w3.org/1998/Math/MathML" display="block"> 2 <mrow> 3 <mi>λ</mi> 4 <mo>=</mo> 5 <mfrac> 6 <mi>x</mi> 7 <mi>a</mi> 8 </mfrac> 9 <mspace width="1em"/> 10 <mo>,</mo> 11 <mspace width="1em"/> 12 <mi>y</mi> 13 <mo>=</mo> 14 <mi>a</mi> 15 <mfenced> 16 <mrow> 17 <mi>λ</mi> 18 <mo>−</mo> 19 <mn>1</mn> 20 <mo>−</mo> 21 <mi>ln</mi> 22 <mi>λ</mi> 23 </mrow> 24 </mfenced> 25 <mo>=</mo> 26 <mo>−</mo> 27 <mi>a</mi> 28 <mfenced> 29 <mrow> 30 <mi>ln</mi> 31 <mfenced> 32 <mrow> 33 <mn>1</mn> 34 <mo>+</mo> 35 <mi>σ</mi> 36 </mrow> 37 </mfenced> 38 <mo>−</mo> 39 <mi>σ</mi> 40 </mrow> 41 </mfenced> 42 <mspace width="1em"/> 43 <mo>;</mo> 44 <mspace width="1em"/> 45 <mi>σ</mi> 46 <mo>=</mo> 47 <mfrac> 48 <mrow> 49 <mi>x</mi> 50 <mo>−</mo> 51 <mi>a</mi> 52 </mrow> 53 <mi>a</mi> 54 </mfrac> 55 </mrow> 56</math> 57 58