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There are 5 subtopics in this chapter:
i) Integration of functions
ii) Integration of trigonometric functions
iii) Techniques of integration
iv) Definite integrals
v) Trapezoidal rule
In integration of functions, you will learn how to integrate using basic rules of integration. Make sure to pay attention to the type of functions involve (which is: linear function).
Next, we are going to integrate the trigonometric functions. You might need to refer to your notes from the first semester (how to use the sum to product and product to sum rule).
However, some of functions are not really straight forward to integrate. We cannot use basic rules of integration. Hence, we need to try to use either substitution, integration by parts or by using partial fractions. If you can see the derivative of the other function, you might want to choose substitution. In integration by parts, make sure to be careful when choosing the u and dv. Normally, we will choose u that is easier to differentiate compare to integrate. Meanwhile, we only use partial fraction if we have polynomial over polynomial. By using partial fraction, we simplified the expression into something that can be solve by using basic rules of integration.
Then, we will learn how to calculate the definite integral. We will substitute the upper and the lower limit of integral. By doing so, you can calculate the area under the curve. After that, you will rotate or revolve the function to calculate the volume.
Lastly, we will try to approximate the area for functions that are hard to integrate. We will use equal width trapezium to approximate the value. Sometimes we might need to compare the value with the exact value that we get after we integrate the function. Make sure to pay more attention to the number of intervals, width as well as the number of ordinates involved when approximating the area using trapezoidal rule.
Sometimes, you can simplify your functions to use the basic rules of integration (which is easier to integrate and can save a lotttttt of time)
Try to all the questions and see if you can crack the secret message that is given in the first slide.
Miss A:
My neighbour is stalking me. I saw him checking my FB profile through my _________
Integration by Substitution is the first technique we try when the integral is not basic enough to be evaluated using one of the anti-derivatives that are given in the standard tables or we can not directly see what the integral will be. The idea is to define a new variable which will allow the difficult starting integrand to be changed from the old variable to a new integrand which is in terms of the new variable.
Read the notes to understand how do we use substitution to integrate non basic functions. Do take note that once you are using substitution, the function that you obtain has to be easier to integrate compared to what you have previously. Otherwise, you might need to use another technique of integration to solve it.
Try your best to answer all questions. You will need a lot of exercise to get more understanding.
Functions often arise as products of other functions, and we may be required to integrate these products. Normally, i'll use this technique if substitution doesn't work.
Read the notes to understand how do we use integration by parts to solve more complicated functions. Sometimes, you might need to do integration by parts more than once (this is the case if your vdu cannot be integrate using basic rules of integration)
Integration by decomposition into partial fractions is the technique that we use when we can rewrite the integrand as the sum of simpler fractions which can then be integrated separately.
Hint:
Before you start, do make sure to check the highest degree for your numerator and denominator. If you have an improper fraction (where the degree of numerator is equal or greater than the denominator), you will need to do long division to change into proper fraction first before integrate.
Choose your path very carefully!
Can you go safely from the ENTRANCE to the EXIT?
Try look at this if you needed to understand more about integration as you can see how to use each formula and try more examples.
P/s: The full solution to each question is given too ^^
Week 1B
Basic Rules & Trigo
Week 2
Techniques
Week 3
Area & Volume
Week 4
Trapezoidal Rule