4.10 Antiderivatives

A function 'F' is called and antiderivative of some function 'f' on interval 'I' if F(x) = f'(x) for all ‘x’  in ‘I’.

 

Example)      F(x) = 2x3

1.  add 1 to 3

2.  divide 2 by 4

f(x) = x4 + C    (C = some constant)

Table of Antidifferential Formulas

f(x)

F(x)

cf(x)

cF(x)

f(x) + g(x)

F(x) + G(x)

xn

cosx

sinx

sinx

-cosx

sec2x

tanx

secxtanx

sec2x

 

 

 

Example)   f’(x) = 8x3 + 12x + 3    f(1) = 6

                  f(x) =  +  + 3x + C

                  f(x) =  2x4 + 6x2 + 3x + C

            6 = 2(1)4 + 6(1)2 + 3(1) + C

            6 = 2 + 6 + 3 + C

            6 = 11 + C

            C = -5

 

 

Example)  f”(x) = x +         f’(1) = 2         f(1) = 1

                 f’(x) =  +

    f’(x) = x2 +  + C 

 f’(x) = x2 +  +                        

 2= (1)2 + (1) + C

             f(x) =  +  +  + C                  C=

                 f(x) =  + x2.5 + x + C

                 f(x) = + x2.5 + x + -

 

 

Therom: If F is an antiderivative of f on an interval I, then the most general antiderivative of f on I is where C is an arbitrary constant

             

                                                F(x) + C