 Similarly, the locus of points whose polar lines pass through "Q" is the first polar of "Q" and this is also a curve of degree "n"−"1".The polar line of a point is "L" if and only if it contains both "P" and "Q", so the poles of "L" are exactly the points of intersection of the two first polars.By Bézout's theorem these curves have ("n"−1)2 points of intersection and these are the poles of "L".