f ( x ) = x^2
f ( a ) = a^2
f ( b ) = b^2
( a | a^2 )
( b | b^2 )
Steigung
m = ( y1 - y2 ) / ( x1 - x2 )
m = ( a^2 - b^2 ) / ( a - b )
m = [ ( a - b ) *( a + b ) ] / ( a - b )
m = a + b
Tangentensteigung = Sekantensteigung
f ´( x ) = 2 x
f ´( x ) = m
2 x = ( a + b )
x = ( a + b ) / 2
P ( ( a + b ) / 2 | [ ( a + b ) / 2 ]^2 )