Part 1:
Showing posts with label ICTD. Show all posts
Showing posts with label ICTD. Show all posts
Using TI 84Plus and simple programme
INTRODUCTION TO TI84 Plus
Programming QUADRATIC INTO TI84
Study the video provided for clarity of concept and greater appreciation of TI84plus.
Task 1: Simulate the programme into your TI84plus. Call it QUAD
Task 2: Extend your learning by considering the case when the answers are not Real ie. Imaginary
QD Question 1 (Hao En)
1) Expansion of 2(2x^2+3) to make life easier for yourself (at least for me). Or you could choose not to.
2) Since 4x^2+6 is a quadratic expression, the accompanying "unknowns" should be in linear form. Hence the Ax+B. As x-1 is linear, the unknown is a constant, giving us C.
3) Multiplying both sides by the common denominator in order for us to be able to solve the question.
4) The substitution method is used here, as it is much more easier than the Comparing Coefficient method. As the expression on the left side is 5, at one glance it should be easy to tell that if we were to use the comparing coefficient method, solving the unknowns using simultaneous equations would be required.
In this case, by substituting x=1, we are able to remove A and B from the equation, leaving us with only C.
5) Looking at the equation, as A is the only one with a x attached to it, we are able to tell that by substituting x=0 we would be able to remove the A. By removing A and using the answer for C we found out earlier, it would effectively leave us with only B.
6) As A is the only one left, any value of x besides the ones that remove A from the equation will work. For simplicity's sake, -1 is used here.
7) Subbing back the unknowns into the partial fractions, and then simplifying them.
8) Rewriting of the answer to make life easier for Mr Johari.
QD Question 1 (Charlene and Jun Jie)
Before we start on the solution for question 1, the answer that we are to find would be the A, B and C not the X.
The first step in solving a partial fraction is to use the formula given. In this case it will be the RHS of the first line.
The second step is to get rid of the denominator by multiplying it. This is shown in green.
The third step is to substitute X, always start with the roots and use simple numbers. This is shown in purple, green and red.
The last statement is how to present your answer. Put 3 dots aligned in a triangular formation and insert the right values for A, B and C. If the answer can be simplified, then simplify it.
The first step in solving a partial fraction is to use the formula given. In this case it will be the RHS of the first line.
The second step is to get rid of the denominator by multiplying it. This is shown in green.
The third step is to substitute X, always start with the roots and use simple numbers. This is shown in purple, green and red.
The last statement is how to present your answer. Put 3 dots aligned in a triangular formation and insert the right values for A, B and C. If the answer can be simplified, then simplify it.
QD Question 6 solution (Jee Hoon, Bowen)
Q : Express
into partial fraction.
Ans : x+1 + 1/x+1 - 4/x-1
Working :
Use long division to divide x^3 -x^2 +2x -6 by x^2 -1 (because it is improper fraction)
x^3 -x^2 +2x -6/x^2-1 = x+1 - 3x+5/x^2-1
3x+5 = A(x-1) + B(x+1)
3x+5 = (A+B)x - A+B
By comparing coefficients :
x^1 : A+B = 3
x^0 : -A+B = 5
A = -1
B = 4
Therefore,
x^3 -x^2 +2x -6/x^2-1 = x+1 + 1/x+1 - 4/x-1
into partial fraction.
Ans : x+1 + 1/x+1 - 4/x-1
Working :
Use long division to divide x^3 -x^2 +2x -6 by x^2 -1 (because it is improper fraction)
x^3 -x^2 +2x -6/x^2-1 = x+1 - 3x+5/x^2-1
3x+5 = A(x-1) + B(x+1)
3x+5 = (A+B)x - A+B
By comparing coefficients :
x^1 : A+B = 3
x^0 : -A+B = 5
A = -1
B = 4
Therefore,
x^3 -x^2 +2x -6/x^2-1 = x+1 + 1/x+1 - 4/x-1
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