Module :MA0001NP Foundation Mathematics Lecture Week 6
Rational Expressions P, Q, R, and S are polynomials Addition Operation Multiplication Subtraction Division Notice the common denominator Reciprocal and Multiply
Addition Simplify
Addition Simplify
Subtraction Simplify
Subtraction Simplify 4
Multiplication Simplify
Multiplication Simplify Factorising (2x-6) 3
Division Simplify 2 2
Solve
Partial fractions Programme F7: Partial fractions Consider the following combination of algebraic fractions: The fractions on the left are called the partial fractions of the fraction on the right.
Partial fractions Find the partial fractions of the following Programme F7: Partial fractions
Partial fractions It is assumed that a partial fraction break down is possible in the form: The assumption is validated by finding the values of A and B. Partial fractions
To find the values of A and B the two partial fractions are added to give:
Partial fractions Programme F7: Partial fractions Since: And since the denominators are identical the numerators must be identical as well. That is:
Partial fractions Programme F7: Partial fractions Consider the identity: Therefore: Therefore Therefore:
Denominators with quadratic factors A similar procedure is applied if one of the factors in the denominator is a quadratic. For example: This results in:
Denominators with quadratic factors Equating coefficients of powers of x yields: Three equations in three unknowns with solution:
Denominators with repeated factors Repeated factors in the denominator of the original fraction of the form: give partial fractions of the form: Partial fractions
Denominators with repeated factors Partial fractions Similarly, repeated factors in the denominator of the original fraction of the form: give partial fractions of the form:
Partial fractions Programme F7: Partial fractions Find the partial fractions for the following expressions : 1.7x+18/(x+2)(x+3) 2.2x-7/x²+5x /2x²+15x x-11/x²-5x+4 5.3x+11/2x²+3x-2
Partial fractions Programme F7: Partial fractions Find the partial fractions for the following expressions : 6.x+21/2(2x+3)(3x-2) 7. x-35/x²-25 8.x-4/x²-6x+9 9.5x+4/-x²-x x-5/9x²-6x+1