public void TestGetCosTheta()
{
var testSubject00 = new LinearEquation(-1, 2);
var testSubject01 = new LinearEquation(1, 3);
var testResult = testSubject00.GetCosTheta(testSubject01);
Console.WriteLine(testResult);
Assert.IsTrue(0.707106781 - testResult < 0.000001);
}