NHoldAll is an attribute which specifies that none of the arguments to a function should be affected by N.
NHoldFirst is an attribute which specifies that the first argument to a function should not be affected by N.
NHoldRest is an attribute which specifies that all but the first argument to a function should not be affected by N.
NicholsGridLines is an option to NicholsPlot that specifies contours of constant magnitude and constant phase of the closed-loop system.
NicholsPlot[g] gives the Nichols plot of a rational function g in one complex variable.NicholsPlot[sys] gives the Nichols plot of a TransferFunctionModel or StateSpaceModel ...
NIntegrate[f, {x, x_min, x_max}] gives a numerical approximation to the integral \[Integral]_x_min^x_max\ f\ d \ x. NIntegrate[f, {x, x_min, x_max}, {y, y_min, y_max}, ...] ...
NMaximize[f, x] maximizes f numerically with respect to x.NMaximize[f, {x, y, ...}] maximizes f numerically with respect to x, y, .... NMaximize[{f, cons}, {x, y, ...}] ...
NMaxValue[f, x] gives the maximum value of f with respect to x.NMaxValue[f, {x, y, ...}] gives the maximum value of f with respect to x, y, .... NMaxValue[{f, cons}, {x, y, ...
NMinimize[f, x] minimizes f numerically with respect to x.NMinimize[f, {x, y, ...}] minimizes f numerically with respect to x, y, .... NMinimize[{f, cons}, {x, y, ...}] ...
NMinValue[f, x] gives the minimum value of f with respect to x.NMinValue[f, {x, y, ...}] gives the minimum value of f with respect to x, y, .... NMinValue[{f, cons}, {x, y, ...