Parabolic tangent equation of high school mathematics 1, the known tangent point Q(x0, y0), if y? = =2px, then the tangent y0y = p (x0+x); If x? = =2py, then tangent x0x = p (y0+y) and so on.
2. The known tangent point Q(x0, y0)
If y? = =2px, then the tangent y0y = p (x0+x).
If x? = =2py, then tangent x0x = p (y0+y).
3. Known tangent slope k
If y? = =2px, then tangent y = kx+p/(2k).
If x? = =2py, then the tangent x = y/k+PK/2 (y = kx-PK? /2)。
Related property 1, the intersection of tangents passing through the two ends of the focal chord of parabola is on the quasi-line of parabola.
2. Tangents at both ends of the parabolic focus chord are perpendicular to each other.
3. The circle whose diameter is parabolic focus chord is tangent to the parabolic directrix.
4. The line between the tangent passing through the focus chord of the parabola and the intersection of the parabola focus is perpendicular to the focus chord.
5. The connecting line between the intersection of tangents at both ends of the focal chord and the midpoint of the focal chord is equally divided by parabola.