10. The Fundamental Theorem of Calculus

Calculus 1



Weiqi Zhou

Motivating Example

  • a particle moves toward a fixed direction along a line, its position at time is

  • then its speed is

  • from time to time ,the distance it traveled is , which is also

  • i.e.,

Fundamental Theorem of Calculus

if is continuous on ,then it has an anti-derivative on

if is an anti-derivative of , then

where the RHS can also be written as or

Existence of Anti-derivatives

  • if is continuous on ,then let

  • by MVT for definite integrals,for any , there is with


  • consequently

Example

  • let ,find

  • using MVT: , s.t.


  • using the chain rule: let

Example and Exercise

  • ,find

  • using the product rule



  • exercise:Find using MVT

Exercises

  • , find

  • , find

  • find

  • if is continuous and positive,show that is monotonically increasing for

Proof of the Newton-Leibniz Formula

  • take

  • then ,

  • any anti-derivative of can be written as , where is a constant



Exercises

  • find

  • find

  • if is determined by ,find

  • if is continuous on ,and ,show that there is only one root for in

Change of Variable

if is continuous on is differentiable,
is a bijection,
,then

Example

  • find

  • let



Exercises

  • find

  • find

  • find

  • find the average value of on

A Simple Observation

if , and is continuous on , then

Exercises

  • find

  • show that

  • let ,find

Integration by Parts

if are continuously differentiable on ,then

Example

  • find

  • take , then

Exercises

  • find

  • find

  • find

  • if ,find

Exercises

show that

Summary

  • FTC

  • Differentiation under Integrals

  • Change of Variable

  • Integration by Parts