Respuesta :

LammettHash
[tex]\displaystyle\frac{\mathrm d}{\mathrm dx}\int_x^0\cos2\pi u\,\mathrm du=-\frac{\mathrm d}{\mathrm dx}\int_0^x\cos2\pi u\,\mathrm du=-\cos2\pi x[/tex]

by the fundamental theorem of calculus.