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Page 1
Integration
Integrand and element of integration
The function under the sign of integration is called integrand. For e.g. in
3
xdx
?
; x
3
is
called integrand. In the integral f(x) dx
?
, dx is known as the element of integration and it
indicates the variable with respect to which the given function is to be integrated.
Constant of integration :
We know that
22
d
(x ) 2x 2xdx x
dx
??
?
Also
2
d
(x c) 2x
dx
?? ?
2
2xdx x c ? ?
?
, where c is any constant
So we notice that x
2
is an integral of 2x, then x
2
+ c is also an integral of 2x. In general if
f(x)dx
?
= ?(x) then
f(x)dx
?
= ?(x) + c
Standard formulae
n1
n
x
xdx c
n1
?
??
?
?
, (n ? ?1)
1
22
1x
sin c
a
ax
?
? ?
?
?
1
dx logx c
x
??
?
1
22
dx x
cos c
a
ax
?
???
?
?
xx
edx e c ??
?
1
22
dx 1 x
tan c
aa
ax
?
? ?
?
?
x
x
e
a
adx
log a
?
?
+ c
1
22
dx 1 x
cot c
aa
ax
?
?
? ?
?
?
cosxdx sinx c ??
?
1
22
dx 1 x
sec c
aa
xx a
?
? ?
?
?
cosecxcotxdx cosecx c ???
?
1
22
dx 1 x
cosec c
aa
xx a
?
?
? ?
?
?
sinxdx cosx c ?? ?
?
sinhxdx
?
= cos h x + c
Page 2
Integration
Integrand and element of integration
The function under the sign of integration is called integrand. For e.g. in
3
xdx
?
; x
3
is
called integrand. In the integral f(x) dx
?
, dx is known as the element of integration and it
indicates the variable with respect to which the given function is to be integrated.
Constant of integration :
We know that
22
d
(x ) 2x 2xdx x
dx
??
?
Also
2
d
(x c) 2x
dx
?? ?
2
2xdx x c ? ?
?
, where c is any constant
So we notice that x
2
is an integral of 2x, then x
2
+ c is also an integral of 2x. In general if
f(x)dx
?
= ?(x) then
f(x)dx
?
= ?(x) + c
Standard formulae
n1
n
x
xdx c
n1
?
??
?
?
, (n ? ?1)
1
22
1x
sin c
a
ax
?
? ?
?
?
1
dx logx c
x
??
?
1
22
dx x
cos c
a
ax
?
???
?
?
xx
edx e c ??
?
1
22
dx 1 x
tan c
aa
ax
?
? ?
?
?
x
x
e
a
adx
log a
?
?
+ c
1
22
dx 1 x
cot c
aa
ax
?
?
? ?
?
?
cosxdx sinx c ??
?
1
22
dx 1 x
sec c
aa
xx a
?
? ?
?
?
cosecxcotxdx cosecx c ???
?
1
22
dx 1 x
cosec c
aa
xx a
?
?
? ?
?
?
sinxdx cosx c ?? ?
?
sinhxdx
?
= cos h x + c
secx tanxdx secx c ??
?
coshxdx
?
= sin h x + c
2
sec x dx tanx c ??
?
2
dx
x1 ?
?
= sin h
?1
x + c
2
cosec xdx
?
= ?cot x + c
2
dx
x1 ?
?
= cos h
?1
x + c
cotxdx
?
= log sin x + c
2
dx
x1 ?
?
= tan h
?1
x + c
tanxdx
?
= log sec x + c tanxdx
?
= ? log (cos x) + c
? ? secxdx log(secx tanx) c ?? ?
?
secxdx ?
?
? ??
x
log tan c
42
???
? ?
??
??
?? ? ? cosec x dx log(cosecx cotx) c ?? ? ?
?
? ? cosec x dx ?
?
x
log tan
2
??
??
??
+ c
Important Trigonometric Identities
? sin
2
A + cos
2
A =1
? sin (A + B) = sin A cos B + cos A sin B
? cos (A + B) = cos A cos B ? sin A sin B
? tan (A + B) =
tanA tanB
1 tanA tanB
?
?
? sin (A ? B) = sin A cos B ? cos A sin B
? cos (A ? B) = cos A cos B + sin A sin B
? tan (A ? B) =
tanA tanB
1 tanA tanB
?
?
? sin
2
A ? sin
2
B = sin (A + B) sin (A ? B)
? cos
2
A ? sin
2
B = cos (A + B) cos (A ? B)
? 2 sin A cos B = sin (A + B) + sin (A ? B)
? 2 cos A sin B = sin (A + B) ? sin (A ? B)
? 2 cos A cos B = cos (A + B) + cos (A ? B)
Page 3
Integration
Integrand and element of integration
The function under the sign of integration is called integrand. For e.g. in
3
xdx
?
; x
3
is
called integrand. In the integral f(x) dx
?
, dx is known as the element of integration and it
indicates the variable with respect to which the given function is to be integrated.
Constant of integration :
We know that
22
d
(x ) 2x 2xdx x
dx
??
?
Also
2
d
(x c) 2x
dx
?? ?
2
2xdx x c ? ?
?
, where c is any constant
So we notice that x
2
is an integral of 2x, then x
2
+ c is also an integral of 2x. In general if
f(x)dx
?
= ?(x) then
f(x)dx
?
= ?(x) + c
Standard formulae
n1
n
x
xdx c
n1
?
??
?
?
, (n ? ?1)
1
22
1x
sin c
a
ax
?
? ?
?
?
1
dx logx c
x
??
?
1
22
dx x
cos c
a
ax
?
???
?
?
xx
edx e c ??
?
1
22
dx 1 x
tan c
aa
ax
?
? ?
?
?
x
x
e
a
adx
log a
?
?
+ c
1
22
dx 1 x
cot c
aa
ax
?
?
? ?
?
?
cosxdx sinx c ??
?
1
22
dx 1 x
sec c
aa
xx a
?
? ?
?
?
cosecxcotxdx cosecx c ???
?
1
22
dx 1 x
cosec c
aa
xx a
?
?
? ?
?
?
sinxdx cosx c ?? ?
?
sinhxdx
?
= cos h x + c
secx tanxdx secx c ??
?
coshxdx
?
= sin h x + c
2
sec x dx tanx c ??
?
2
dx
x1 ?
?
= sin h
?1
x + c
2
cosec xdx
?
= ?cot x + c
2
dx
x1 ?
?
= cos h
?1
x + c
cotxdx
?
= log sin x + c
2
dx
x1 ?
?
= tan h
?1
x + c
tanxdx
?
= log sec x + c tanxdx
?
= ? log (cos x) + c
? ? secxdx log(secx tanx) c ?? ?
?
secxdx ?
?
? ??
x
log tan c
42
???
? ?
??
??
?? ? ? cosec x dx log(cosecx cotx) c ?? ? ?
?
? ? cosec x dx ?
?
x
log tan
2
??
??
??
+ c
Important Trigonometric Identities
? sin
2
A + cos
2
A =1
? sin (A + B) = sin A cos B + cos A sin B
? cos (A + B) = cos A cos B ? sin A sin B
? tan (A + B) =
tanA tanB
1 tanA tanB
?
?
? sin (A ? B) = sin A cos B ? cos A sin B
? cos (A ? B) = cos A cos B + sin A sin B
? tan (A ? B) =
tanA tanB
1 tanA tanB
?
?
? sin
2
A ? sin
2
B = sin (A + B) sin (A ? B)
? cos
2
A ? sin
2
B = cos (A + B) cos (A ? B)
? 2 sin A cos B = sin (A + B) + sin (A ? B)
? 2 cos A sin B = sin (A + B) ? sin (A ? B)
? 2 cos A cos B = cos (A + B) + cos (A ? B)
? 2 sin A sin B = cos (A ? B) ? cos (A + B)
? 2 sin
CD
2
?
cos
CD
2
?
= sin C + sin D
? 2 cos
CD
2
?
sin
CD
2
?
= sin C ? sin D
? 2 cos
CD
2
?
cos
CD
2
?
= cos C + cos D
? 2 sin
CD
2
?
sin
DC
2
?
= cos C ? cos D
? cos 2A = cos
2
A ? sin
2
A = 1 ? 2sin
2
A = 2 cos
2
A ? 1 =
2
2
1tan A
1tan A
?
?
? sin 2A = 2 sin A cos A =
2
2tanA
1tan A ?
? tan 2A =
2
2tanA
1tan A ?
? sin 3A = 3 sin A ? 4 sin
3
A
? cos 3A = 4 cos
3
A ? 3 cos A
? tan 3A =
3
2
3tanA 4tan A
13tan A
?
?
Note : Integration of
mn
sin xcos xdx
?
where m and n are positive integers
(i) If m be odd and n be even, for integration put t = cos x
(ii) If m be even and n be odd, for integration put t = sin x
(iii) If m and n are odd, for integration put either t = cos x or sin x
(iv) If m and n are even, for integration put either t = cos x or sin x
Solved Example 17 :
Evaluate
3
sin x dx
?
Solution :
sin 3x = 3 sin x ? 4 sin
3
x
4 sin
3
x = 3 sin x ? sin 3x
? 4
3
sin x dx
?
= ??
?
(3sinx sin3x) dx
? ??
??
3sinxdx sin3xdx
3
1cos3x
sin xdx 3cosx c
43
??
? ?? ?
??
??
?
Page 4
Integration
Integrand and element of integration
The function under the sign of integration is called integrand. For e.g. in
3
xdx
?
; x
3
is
called integrand. In the integral f(x) dx
?
, dx is known as the element of integration and it
indicates the variable with respect to which the given function is to be integrated.
Constant of integration :
We know that
22
d
(x ) 2x 2xdx x
dx
??
?
Also
2
d
(x c) 2x
dx
?? ?
2
2xdx x c ? ?
?
, where c is any constant
So we notice that x
2
is an integral of 2x, then x
2
+ c is also an integral of 2x. In general if
f(x)dx
?
= ?(x) then
f(x)dx
?
= ?(x) + c
Standard formulae
n1
n
x
xdx c
n1
?
??
?
?
, (n ? ?1)
1
22
1x
sin c
a
ax
?
? ?
?
?
1
dx logx c
x
??
?
1
22
dx x
cos c
a
ax
?
???
?
?
xx
edx e c ??
?
1
22
dx 1 x
tan c
aa
ax
?
? ?
?
?
x
x
e
a
adx
log a
?
?
+ c
1
22
dx 1 x
cot c
aa
ax
?
?
? ?
?
?
cosxdx sinx c ??
?
1
22
dx 1 x
sec c
aa
xx a
?
? ?
?
?
cosecxcotxdx cosecx c ???
?
1
22
dx 1 x
cosec c
aa
xx a
?
?
? ?
?
?
sinxdx cosx c ?? ?
?
sinhxdx
?
= cos h x + c
secx tanxdx secx c ??
?
coshxdx
?
= sin h x + c
2
sec x dx tanx c ??
?
2
dx
x1 ?
?
= sin h
?1
x + c
2
cosec xdx
?
= ?cot x + c
2
dx
x1 ?
?
= cos h
?1
x + c
cotxdx
?
= log sin x + c
2
dx
x1 ?
?
= tan h
?1
x + c
tanxdx
?
= log sec x + c tanxdx
?
= ? log (cos x) + c
? ? secxdx log(secx tanx) c ?? ?
?
secxdx ?
?
? ??
x
log tan c
42
???
? ?
??
??
?? ? ? cosec x dx log(cosecx cotx) c ?? ? ?
?
? ? cosec x dx ?
?
x
log tan
2
??
??
??
+ c
Important Trigonometric Identities
? sin
2
A + cos
2
A =1
? sin (A + B) = sin A cos B + cos A sin B
? cos (A + B) = cos A cos B ? sin A sin B
? tan (A + B) =
tanA tanB
1 tanA tanB
?
?
? sin (A ? B) = sin A cos B ? cos A sin B
? cos (A ? B) = cos A cos B + sin A sin B
? tan (A ? B) =
tanA tanB
1 tanA tanB
?
?
? sin
2
A ? sin
2
B = sin (A + B) sin (A ? B)
? cos
2
A ? sin
2
B = cos (A + B) cos (A ? B)
? 2 sin A cos B = sin (A + B) + sin (A ? B)
? 2 cos A sin B = sin (A + B) ? sin (A ? B)
? 2 cos A cos B = cos (A + B) + cos (A ? B)
? 2 sin A sin B = cos (A ? B) ? cos (A + B)
? 2 sin
CD
2
?
cos
CD
2
?
= sin C + sin D
? 2 cos
CD
2
?
sin
CD
2
?
= sin C ? sin D
? 2 cos
CD
2
?
cos
CD
2
?
= cos C + cos D
? 2 sin
CD
2
?
sin
DC
2
?
= cos C ? cos D
? cos 2A = cos
2
A ? sin
2
A = 1 ? 2sin
2
A = 2 cos
2
A ? 1 =
2
2
1tan A
1tan A
?
?
? sin 2A = 2 sin A cos A =
2
2tanA
1tan A ?
? tan 2A =
2
2tanA
1tan A ?
? sin 3A = 3 sin A ? 4 sin
3
A
? cos 3A = 4 cos
3
A ? 3 cos A
? tan 3A =
3
2
3tanA 4tan A
13tan A
?
?
Note : Integration of
mn
sin xcos xdx
?
where m and n are positive integers
(i) If m be odd and n be even, for integration put t = cos x
(ii) If m be even and n be odd, for integration put t = sin x
(iii) If m and n are odd, for integration put either t = cos x or sin x
(iv) If m and n are even, for integration put either t = cos x or sin x
Solved Example 17 :
Evaluate
3
sin x dx
?
Solution :
sin 3x = 3 sin x ? 4 sin
3
x
4 sin
3
x = 3 sin x ? sin 3x
? 4
3
sin x dx
?
= ??
?
(3sinx sin3x) dx
? ??
??
3sinxdx sin3xdx
3
1cos3x
sin xdx 3cosx c
43
??
? ?? ?
??
??
?
Solved Example 18 :
Evaluate sin3x cos2x dx
?
Solution :
1
sin3xcos2xdx (sin5x sinx)dx
2
??
??
=
11
cos5x cos x
10 2
?
?
Solved Example 19 :
Evaluate sin2xsin3xdx
?
Solution :
?? ? ? ?
??
1
sin2x sin3x dx cos x cos5x dx
2
=
11
sinx sin5x
210
?
Solved Example 20 :
Integrate
22
dx
cos xsin x
?
Solution :
Now,
?
?
22
22 22
1cosxsinx
cos x sin x cos x sin x
??
22
11
sin x cos x
= cosec
2
x + sec
2
x
[ ?1 = sin
2
x + cos
2
x]
?
22
dx
cos xsin x
?
=
22
(cosec x sec x)dx ?
?
=
22
cosec xdx sec xdx ?
??
= ? cot x + tan x + c
Solved Example 21 :
Evaluate
33
sin x cos xdx
?
Solution :
We have
sin
3
x cos
3
x = (sin x cos x)
3
=
1
8
(2 sin x cos x)
3
=
1
8
sin
3
2x
=
11
84
? (3 sin 2x ? sin 6x)
[ ? 4 sin
3
x = 3 sin x ? sin 3x]
=
1
32
(3 sin 2x ? sin 6x)
?
?
33
sin x cos xdx
??
?
1
(3sin2x sin6x)dx
32
=
31
sin2xdx sin6xdx
32 32
?
??
=
3 cos2x 1 cos6x
c
32 2 32 6
?? ?? ??
? ?
?? ??
?? ??
Hence ?
?
33
sin x cos x dx
?
? ??
31
cos2x cos6x c
64 192
Solved Example 22 :
Evaluate
1
dx
1sinx ?
?
Solution :
111sinx
1 sinx 1 sinx 1 sinx
?
??
?? ?
=
?
?
2
1sinx
1sin x
Page 5
Integration
Integrand and element of integration
The function under the sign of integration is called integrand. For e.g. in
3
xdx
?
; x
3
is
called integrand. In the integral f(x) dx
?
, dx is known as the element of integration and it
indicates the variable with respect to which the given function is to be integrated.
Constant of integration :
We know that
22
d
(x ) 2x 2xdx x
dx
??
?
Also
2
d
(x c) 2x
dx
?? ?
2
2xdx x c ? ?
?
, where c is any constant
So we notice that x
2
is an integral of 2x, then x
2
+ c is also an integral of 2x. In general if
f(x)dx
?
= ?(x) then
f(x)dx
?
= ?(x) + c
Standard formulae
n1
n
x
xdx c
n1
?
??
?
?
, (n ? ?1)
1
22
1x
sin c
a
ax
?
? ?
?
?
1
dx logx c
x
??
?
1
22
dx x
cos c
a
ax
?
???
?
?
xx
edx e c ??
?
1
22
dx 1 x
tan c
aa
ax
?
? ?
?
?
x
x
e
a
adx
log a
?
?
+ c
1
22
dx 1 x
cot c
aa
ax
?
?
? ?
?
?
cosxdx sinx c ??
?
1
22
dx 1 x
sec c
aa
xx a
?
? ?
?
?
cosecxcotxdx cosecx c ???
?
1
22
dx 1 x
cosec c
aa
xx a
?
?
? ?
?
?
sinxdx cosx c ?? ?
?
sinhxdx
?
= cos h x + c
secx tanxdx secx c ??
?
coshxdx
?
= sin h x + c
2
sec x dx tanx c ??
?
2
dx
x1 ?
?
= sin h
?1
x + c
2
cosec xdx
?
= ?cot x + c
2
dx
x1 ?
?
= cos h
?1
x + c
cotxdx
?
= log sin x + c
2
dx
x1 ?
?
= tan h
?1
x + c
tanxdx
?
= log sec x + c tanxdx
?
= ? log (cos x) + c
? ? secxdx log(secx tanx) c ?? ?
?
secxdx ?
?
? ??
x
log tan c
42
???
? ?
??
??
?? ? ? cosec x dx log(cosecx cotx) c ?? ? ?
?
? ? cosec x dx ?
?
x
log tan
2
??
??
??
+ c
Important Trigonometric Identities
? sin
2
A + cos
2
A =1
? sin (A + B) = sin A cos B + cos A sin B
? cos (A + B) = cos A cos B ? sin A sin B
? tan (A + B) =
tanA tanB
1 tanA tanB
?
?
? sin (A ? B) = sin A cos B ? cos A sin B
? cos (A ? B) = cos A cos B + sin A sin B
? tan (A ? B) =
tanA tanB
1 tanA tanB
?
?
? sin
2
A ? sin
2
B = sin (A + B) sin (A ? B)
? cos
2
A ? sin
2
B = cos (A + B) cos (A ? B)
? 2 sin A cos B = sin (A + B) + sin (A ? B)
? 2 cos A sin B = sin (A + B) ? sin (A ? B)
? 2 cos A cos B = cos (A + B) + cos (A ? B)
? 2 sin A sin B = cos (A ? B) ? cos (A + B)
? 2 sin
CD
2
?
cos
CD
2
?
= sin C + sin D
? 2 cos
CD
2
?
sin
CD
2
?
= sin C ? sin D
? 2 cos
CD
2
?
cos
CD
2
?
= cos C + cos D
? 2 sin
CD
2
?
sin
DC
2
?
= cos C ? cos D
? cos 2A = cos
2
A ? sin
2
A = 1 ? 2sin
2
A = 2 cos
2
A ? 1 =
2
2
1tan A
1tan A
?
?
? sin 2A = 2 sin A cos A =
2
2tanA
1tan A ?
? tan 2A =
2
2tanA
1tan A ?
? sin 3A = 3 sin A ? 4 sin
3
A
? cos 3A = 4 cos
3
A ? 3 cos A
? tan 3A =
3
2
3tanA 4tan A
13tan A
?
?
Note : Integration of
mn
sin xcos xdx
?
where m and n are positive integers
(i) If m be odd and n be even, for integration put t = cos x
(ii) If m be even and n be odd, for integration put t = sin x
(iii) If m and n are odd, for integration put either t = cos x or sin x
(iv) If m and n are even, for integration put either t = cos x or sin x
Solved Example 17 :
Evaluate
3
sin x dx
?
Solution :
sin 3x = 3 sin x ? 4 sin
3
x
4 sin
3
x = 3 sin x ? sin 3x
? 4
3
sin x dx
?
= ??
?
(3sinx sin3x) dx
? ??
??
3sinxdx sin3xdx
3
1cos3x
sin xdx 3cosx c
43
??
? ?? ?
??
??
?
Solved Example 18 :
Evaluate sin3x cos2x dx
?
Solution :
1
sin3xcos2xdx (sin5x sinx)dx
2
??
??
=
11
cos5x cos x
10 2
?
?
Solved Example 19 :
Evaluate sin2xsin3xdx
?
Solution :
?? ? ? ?
??
1
sin2x sin3x dx cos x cos5x dx
2
=
11
sinx sin5x
210
?
Solved Example 20 :
Integrate
22
dx
cos xsin x
?
Solution :
Now,
?
?
22
22 22
1cosxsinx
cos x sin x cos x sin x
??
22
11
sin x cos x
= cosec
2
x + sec
2
x
[ ?1 = sin
2
x + cos
2
x]
?
22
dx
cos xsin x
?
=
22
(cosec x sec x)dx ?
?
=
22
cosec xdx sec xdx ?
??
= ? cot x + tan x + c
Solved Example 21 :
Evaluate
33
sin x cos xdx
?
Solution :
We have
sin
3
x cos
3
x = (sin x cos x)
3
=
1
8
(2 sin x cos x)
3
=
1
8
sin
3
2x
=
11
84
? (3 sin 2x ? sin 6x)
[ ? 4 sin
3
x = 3 sin x ? sin 3x]
=
1
32
(3 sin 2x ? sin 6x)
?
?
33
sin x cos xdx
??
?
1
(3sin2x sin6x)dx
32
=
31
sin2xdx sin6xdx
32 32
?
??
=
3 cos2x 1 cos6x
c
32 2 32 6
?? ?? ??
? ?
?? ??
?? ??
Hence ?
?
33
sin x cos x dx
?
? ??
31
cos2x cos6x c
64 192
Solved Example 22 :
Evaluate
1
dx
1sinx ?
?
Solution :
111sinx
1 sinx 1 sinx 1 sinx
?
??
?? ?
=
?
?
2
1sinx
1sin x
?
?? ?
22 2
1sinx 1 sinx
cosx cosx cosx
or
1
1sinx ?
= sec
2
x ? tan x sec x
?
?
?
1
dx
1sinx
??
?
2
(sec x tanxsec x)dx
= ?? ?
??
2
sec x dx tanx sec x dx
?? ? tanx sec x c
Solved Example 23 :
Evaluate
76
sin x cos xdx
?
Solution :
?
?
76
sin x cos x dx
?
?
66
sin x cos x sinxdx
=
23 6
(1 cos x) cos xsinxdx ?
?
= ?? ?
?
24 6
(1 3cos x 3cos x cos x)
6
cos x sinxdx
= ?? ?
?
68 10 12
(cos x 3cos x 3cos x cos x)
sinxdx
=
6 8 10 12
(t 3t 3t t )dt ?? ? ?
?
by putting t = cos x
= ?
7 9 11 13
tt t t
33
7 9 11 13
?? ?
= ? ??
79 11
11 3
cos x cos x cos x
73 11
?
13
1
cos x
13
Solved Example 24 :
Evaluate
63
sin x cos xdx
?
Solution :
?? ?
??
63 6 2
sin x cos x dx sin x(1 sin x)cos xdx
=
68
(sin x sin x)cos x dx ?
?
=
68
(t t )dt ?
?
? by putting
sin x = t =
79
11
tt
79
? =
79
11
sin x sin x
79
?
Solved Example 25 :
Evaluate
42
sin x cos xdx
?
Solution :
sin
4
x cos
2
x
=
1
8
(2 sin
2
x)
2
(1+cos2x)
=
1
8
(1 ?cos2x ? cos
2
2x + cos
3
2x)
=
1
8
? ?
??
?
?
1cos4x
1cos2x
2
? ?
?
?
?
cos6x 3cos2x
4
=
1
8
11 1 1
cos2x cos4x cos6x
24 2 4
??
???
??
??
=
11 1
1cos2x cos4x cos6x
16 2 2
??
?? ?
??
??
?
42
sin x cos xdx
=
??
?? ?
??
??
11 1
1 cos2x cos4x cos6x dx
16 2 2
=
11 1 1
xsin2x sin4x sin6x
16 4 4 12
??
???
??
??
Read More
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65 videos|129 docs|94 tests
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| 1. What is integration in mathematics? | ![]() |
| 2. How is integration used in real life? | ![]() |
| 3. What are the different methods of integration? | ![]() |
| 4. What is the fundamental theorem of calculus related to integration? | ![]() |
| 5. How can integration be used to solve problems in physics? | ![]() |