Straight line — one of the basic concepts of geometry. It is set on the plane by the equation like Ax + By = C. The number equal to A/B is equal to a tangent of angle of an inclination of a straight line or as it is called still, to slope of a straight line.
It is required to you
- Knowledge of geometry.
Instruction
1. Let two straight lines with Ax equations + be given to By = C and Dx + Ey = F. Let's express from these equations of straight lines tilt angle coefficient. For the first direct this coefficient is equal to A/B, and for the second D/E respectively. For descriptive reasons we will review an example. The equation of the first straight line 4x+6y=20, the equation of the second straight line - 3x+5y=3. Coefficients of a tilt angle will be respectively equal: 0.67 and-0.6.
2. Now it is necessary to find a tilt angle of each straight line. For this purpose we will count an arctangent from slope. Tilt angles of straight lines will be equal in the reviewed example to arctg (0.67) = 34 degrees and arctg(-0.6) =-31 degrees respectively.
3. So one straight line is able to do negative slope, and the second positive, the corner between these straight lines will be equal to the sum of absolute values of these corners. In a case when slopes both are negative or both are positive, the corner is by subtraction from a bigger corner smaller. In the reviewed example we will receive that the corner between straight lines is equal |34| + |-31| = 34 + 31 = 65 degrees.