How do you know if the equation is Linear or non-linear?

[mazdaspring]

Can anyone please explain to me how can we know if the engineering equation is linear or non linear?

 

[KlausST]

Hi,

y = mx + b

is linear.

m is the slope (it may be negative, zero or positive)
b is the offset (it may be negative, zero or positive)

Everything else is not linear. (If I remember right)

Klaus

 

[c_mitra]

Can anyone please explain to me how can we know if the engineering equation is linear or non linear?

Please tell me your engineering equation and perhaps I can tell you whether the equation is linear from a mathematics viewpoint.

If the function f(z) depends only on z (a.z+b or a form that can be converted to this; if a is zero then the function is a constant function; the constants a and b can be real or complex) then the function is linear. Electrical and electronic equations are mostly complex functions and they have poles and branch cuts and singularities that are really messy when you come to complex numbers.

 

[kthackst]

In electrical engineering terms, we often define a component or material as linear if it behaves the same regardless of the magnitude of the excitation. For example, an ideal resistor and capacitor will act the same regardless of how much power I put through them. A diode will not, so it is a non-linear component.

You can do a quick sanity check of your data quickly based on this, if you're getting non-linear data but expect linear, you might want to check the specs of your system.

 

[andre_luis]

Can anyone please explain to me how can we know if the engineering equation is linear or non linear?

Even a non-linear equation, when computed at a very small range could exhibit a nearly linear shape, regardless of not being represented by the model y=ax+b.There are many approaches that you could experiment to numerically quantify how much an equation behaves as linear or not, and my first attempt would be utilizing the root mean square, comparing the calculated values of your equation against the linear equation obtained by this method.