Step 1: Ensure proper fraction. If deg(P) >= deg(Q), perform polynomial long division: P/Q = quotient + remainder/Q.
Step 2: Factor the denominator Q(x). Over the reals, Q factors into products of linear factors (x-a)^k and irreducible quadratic factors ()^m where < 0.
Step 3: Write the decomposition form.
- Linear (x-a):
- Repeated linear (x-a)^k: + ^2 + ... + ^k
- Quadratic ():
- Repeated quadratic: stack with increasing powers in denominator
Step 4: Find coefficients.
- Cover-up: For distinct linear factor (x-a), set x=a after removing (x-a). Quick and efficient.
- Substitution: Plug in convenient x values (usually roots of Q).
- Coefficient comparison: Match coefficients of powers of x on both sides.
Step 5: Integrate each term.
- => A*ln|x-a|
- ^n (n>1) => A*(x-a)^
- : write Ax+B = (2x+p) + (B-Ap/2). First part gives log, second gives arctan after completing the square.
Common JEE types:
- (x-b)): two distinct linear factors
- ): multiply by x^^(n-1), then substitute t =
- ()): two quadratic factors