Auf der Gerade gilt

${\displaystyle {}y={\frac {7}{5}}-{\frac {4}{5}}x\,}$

und daher ist die eingeschränkte Funktion in der einen Variablen ${\displaystyle {}x}$ durch

${\displaystyle {}{\begin{aligned}x^{2}-x{\left({\frac {7}{5}}-{\frac {4}{5}}x\right)}+3{\left({\frac {7}{5}}-{\frac {4}{5}}x\right)}\cos \left(x+2{\left({\frac {7}{5}}-{\frac {4}{5}}x\right)}\right)&=x^{2}-{\frac {7}{5}}x+{\frac {4}{5}}x^{2}+{\left({\frac {21}{5}}-{\frac {12}{5}}x\right)}\cos \left(x+{\frac {14}{5}}-{\frac {8}{5}}x\right)\\&=-{\frac {7}{5}}x+{\frac {9}{5}}x^{2}+{\left(-{\frac {12}{5}}x+{\frac {21}{5}}\right)}\cos \left(-{\frac {3}{5}}x+{\frac {14}{5}}\right).\end{aligned}}}$