f ( x ) = x3
( x | f ( x ) )
2.Punkt
( x + h | f ( x + h ) )
( f ( x + h ) - f ( x ) ) / ( x + h - x )
( ( x + h ) 3 - x3 ) / h
[ ( x2 + 2xh + h2 ) * ( x + h ) - x3 ] / h
( x3 + 2x2h + xh2 + x2h+ 2xh2 + h3 - x3 ) / h
( 2x2h + xh2 + x2h + 2xh2 + h3 ) / h
h * ( 2x2 + xh + x2 + 2xh + h ) / h
lim h -> 0 [ 2x2 + xh + x2 + 2xh + h ] = 3x2
f ´( x ) = 3 * x2