exposure - When I change the EV compensation, how will that affect my aperture, shutter speed, or ISO?

Let say that we have the following values, as an example:

Shutter speed: 1/40
Aperture: 2
ISO: 1000

How can I get the EV number for this exposure, extract (or add) an EV value (0.33, 0.66 etc.) and calculate back the new shutter speed (or ISO) value?

In fact I want to calculate how the Exposure Compensation will affect my values.

Answer

The Exposure value can be calculated with the given Aperture and shutter speed using the following formula:
(src: wikipedia)
where,
N: Aperture value
t: Shutter Speed

The above EV is for ISO 100 called as EV100. EV For subsequent ISO values is calulated with help of EV100 using the following formula:


where,
EV100: EV from the first formula
S : required ISO value

The Exposure compensation works by adding or subtracting the required Exposure compensation value with the current EV to get the new EV.
This new EV can be reverse engineered with the above formulas to get the Aperture and Shutter speeds.

Applying the values you have given:

EV100 = 7.32  //At ISO 100
EV1000 = 7.32 + 3.32 = 10.64  //At ISO 1000

On applying Exposure Compensation of 0.33:

EV(new) = 10.62 +0.33 = 10.95

Now reverse engineer this value to get N and t accordingly.