addScaledVector( v, s ) {

		this.x += v.x * s;
		this.y += v.y * s;
		this.z += v.z * s;
		this.w += v.w * s;

		return this;

	}
Adds the given vector scaled by the given factor to this instance.

@param {Vector4} v - The vector.
@param {number} s - The factor that scales `v`.
@return {Vector4} A reference to this vector.