1<math xmlns="http://www.w3.org/1998/Math/MathML" display="block"> 2 <mrow> 3 <msub> 4 <mi>x</mi> 5 <mrow> 6 <mi>N</mi> 7 <mo>+</mo> 8 <mn>1</mn> 9 </mrow> 10 </msub> 11 <mspace width="1em"/> 12 <mo>=</mo> 13 <mspace width="1em"/> 14 <msub> 15 <mi>x</mi> 16 <mi>N</mi> 17 </msub> 18 <mo>−</mo> 19 <mfrac> 20 <mrow> 21 <mn>2</mn> 22 <mi>f</mi> 23 <mfenced> 24 <mrow> 25 <mi>x</mi> 26 </mrow> 27 </mfenced> 28 <mi>f</mi> 29 <mo>′</mo> 30 <mfenced> 31 <mrow> 32 <mi>x</mi> 33 </mrow> 34 </mfenced> 35 </mrow> 36 <mrow> 37 <mn>2</mn> 38 <msup> 39 <mfenced> 40 <mrow> 41 <mi>f</mi> 42 <mo>′</mo> 43 <mfenced> 44 <mrow> 45 <mi>x</mi> 46 </mrow> 47 </mfenced> 48 </mrow> 49 </mfenced> 50 <mn>2</mn> 51 </msup> 52 <mo>−</mo> 53 <mi>f</mi> 54 <mfenced> 55 <mrow> 56 <mi>x</mi> 57 </mrow> 58 </mfenced> 59 <mi>f</mi> 60 <mo>″</mo> 61 <mfenced> 62 <mrow> 63 <mi>x</mi> 64 </mrow> 65 </mfenced> 66 </mrow> 67 </mfrac> 68 </mrow> 69</math> 70 71