What is Vander Wall equation

The vander waals equation of state approaches the ideal gas law PV=nRT asthe values of these constant approach zero. The constant a provides a correction for the intermolecular force. Constant b is a correction for finite molecular size and its value is the volume of one mole of the atoms or molecules.
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The vander waals equation was proposed in the year 1873. It was first step towards taking into account interaction forces which are acting between real gases molecules. The equation of state of the perfect aes refers to a gas consisting of point like items which do not interact with one another. Instead of this vander waals proposed an equation -------- (v-b)[p+a/v^]=RT where a and b are called vander waals constant and which have different value for each gas.
(p+a/v^2)(v-b)=RT ....... I M NOT SURE... ?