(ii) xA
xkxA
dx
2
422
−
∫ ++
Divide numerator and denominator by x^2
and substitute x A
x
+=t, A being positive
constant.
(iii) ax bx c
px qx r
dx
2
2
++
∫ ++
put ax^2 + bx + c = l(px^2 + qx + r) + m
d
dx()px qx r n
⎛ (^2) ++
⎝⎜
⎞
⎠⎟+^
Find l, m and n by equating coefficients of
like powers of x and then split the integral
into three integrals.
TRIGONOMETRIC INTEGRALS
To find the integral axb x
cxd x
sin cos dx
sin cos
∫ +
Put a sinx + b cosx
= L (Denominator) +M (Derivative of denominator)
Note : To evaluate the integration of the forms
dx
axb x
dx
ab x
dx
(^22) sin 2 2cos (^2) ab (^2) x
,
sin
,
cos
,
∫∫+++∫
dx
axb x
dx
∫( sin +++cos ) 222 ∫absin xccosx
and
Step 1 : Divide by cos^2 x in each case.
Step 2 : Put tanxt dt
at bt c
∫ ++
to get the form 2 which
is already discussed.
INTEGRALS OF THE FORM
(i) dx
∫axb xsin + cos
(ii)
dx
∫ab x+ sin
(iii)
dx
∫ab x+ cos (iv)
dx
∫axb xcsin ++cos
For all the cases (i), (ii), (iii) and (iv), universal
substitutiontan , sin tan( / )
tan ( / )
x tx x
2 x
22
122
&
cos tan ( / )
tan ( / )
x x
x
= −
12
12
2
2 are used. This substitution convert
the integrals in the form dt
∫at (^2) ++bt c
.
In (i), (ii) and (iii); if a = b, then they becomes
11
1
1
a 1
dx
xxa
dx
xa
dx
sin cos x
,
sin
,
∫∫+++∫ cos
FUNDAMENTAL THEOREM ON CALCULUS
I. Let f be a continuous function on closed
interval [α, β] and A(x) be the area of function.
Then A′(x) = f(x) ∀ x ∈ [α, β]
II. Let f be the continuous function on closed
interval [α, β] and F be an anti-derivative of f.
Then ∫fx dx Fx() =[]()αβ=F() ( )−F
α
β
βα
DEFINITE INTEGRAL AS THE LIMIT OF A SUM
An alternative method of finding fx dx()
α
β
∫ is that
the definite integral fx dx()
α
β
∫ is a limiting case of
the summation of an infinite series provided f(x) is
continuous on [α, β], i.e.,
fxdx( ) lim [ ( )h hf f( h) ... f( (n ) )]h
α
β
∫ =+++++→ 0 αα α−^1
where h
n
=βα−
PROPERTIES OF DEFINITE INTEGRALS
(i) ∫∫f x dx() = f t dt()
α
β
α
β
(ii) ∫∫αfx dx() =− fx dx()
β
β
α
(iii) (a) ∫∫∫fxdx() =+fxdx() fxdx() , <<
α
β
α
γ
γ
β
whereαγβ
(b) fx dx fx dx fx dx fx dx
c
c c
c
n
∫∫() =+ ++() ∫ () ...∫()
α
β
α
1 β
1
2
(iv) ∫∫f x dx() = f(−x dx)
00
αα
α
(v) ∫∫f x dx() =+f( −x dx)
α
β
α
β
αβ
(vi) fx dx
fxdx f x fx
fx fx
()
() , ( ) ()
,()()
− =
− =−
⎧
⎨
⎪
⎩⎪
−∫
∫
α
α
α
2
0
0
if
if
(vii) fxdx fxdx f x fx
fxfx
()
() , ( ) ()
,()()
− =
− =−
⎧
⎨
⎪
⎩⎪
∫ ∫
0
2
0
22
02
α α α
α
if
if
(viii) If f(t) is an odd function then gx ftdt
a
x
()=∫ ()
is an even function.
(ix) If f(t) is an even function then gxftdt
x
()=∫ ()
is an odd function.^0