17. (ii) (1990)
xy graphheConsider t
0allforincreasingisgraphthat theShowa) x
0whenincreasingisCurve
dx
dy
xdx
dy
xy
2
1
18. (ii) (1990)
xy graphheConsider t
0allforincreasingisgraphthat theShowa) x
0whenincreasingisCurve
dx
dy
xdx
dy
xy
2
1
0for0 x
dx
dy
19. (ii) (1990)
xy graphheConsider t
0allforincreasingisgraphthat theShowa) x
0whenincreasingisCurve
dx
dy
xdx
dy
xy
2
1
0for0 x
dx
dy
0,0at yx
20. (ii) (1990)
xy graphheConsider t
0allforincreasingisgraphthat theShowa) x
0whenincreasingisCurve
dx
dy
xdx
dy
xy
2
1
0for0 x
dx
dy
0,0at yx
0,0when yx
21. (ii) (1990)
xy graphheConsider t
0allforincreasingisgraphthat theShowa) x
0whenincreasingisCurve
dx
dy
xdx
dy
xy
2
1
0for0 x
dx
dy
0,0at yx
0,0when yx
0forincreasingiscurve x
47. Hence the result is true for n = k +1 if it is also true for n =k
48. Hence the result is true for n = k +1 if it is also true for n =k
Since the result is true for n = 1 then it is also true for n =1+1 i.e. n=2,
and since the result is true for n = 2 then it is also true for n =2+1 i.e.
n=3, and so on for all positive integral values of n
49. Hence the result is true for n = k +1 if it is also true for n =k
Since the result is true for n = 1 then it is also true for n =1+1 i.e. n=2,
and since the result is true for n = 2 then it is also true for n =2+1 i.e.
n=3, and so on for all positive integral values of n
hundrednearesttheto1000021
estimate;toc)andb)Used)
50. Hence the result is true for n = k +1 if it is also true for n =k
Since the result is true for n = 1 then it is also true for n =1+1 i.e. n=2,
and since the result is true for n = 2 then it is also true for n =2+1 i.e.
n=3, and so on for all positive integral values of n
hundrednearesttheto1000021
estimate;toc)andb)Used)
n
n
nnn
6
34
21
3
2
51. Hence the result is true for n = k +1 if it is also true for n =k
Since the result is true for n = 1 then it is also true for n =1+1 i.e. n=2,
and since the result is true for n = 2 then it is also true for n =2+1 i.e.
n=3, and so on for all positive integral values of n
hundrednearesttheto1000021
estimate;toc)andb)Used)
n
n
nnn
6
34
21
3
2
10000
6
3100004
10000211000010000
3
2
52. Hence the result is true for n = k +1 if it is also true for n =k
Since the result is true for n = 1 then it is also true for n =1+1 i.e. n=2,
and since the result is true for n = 2 then it is also true for n =2+1 i.e.
n=3, and so on for all positive integral values of n
hundrednearesttheto1000021
estimate;toc)andb)Used)
n
n
nnn
6
34
21
3
2
10000
6
3100004
10000211000010000
3
2
6667001000021666700
53. Hence the result is true for n = k +1 if it is also true for n =k
Since the result is true for n = 1 then it is also true for n =1+1 i.e. n=2,
and since the result is true for n = 2 then it is also true for n =2+1 i.e.
n=3, and so on for all positive integral values of n
hundrednearesttheto1000021
estimate;toc)andb)Used)
n
n
nnn
6
34
21
3
2
10000
6
3100004
10000211000010000
3
2
6667001000021666700
hundrednearesttheto6667001000021
55. (iii) Prove x > sinx , for x > 0
1
y
x 2
y = x
y = sinx
56. (iii) Prove x > sinx , for x > 0
1
y
x 2
y = x
y = sinx
( )
'( ) 1
f x x
f x
57. (iii) Prove x > sinx , for x > 0
1
y
x 2
y = x
y = sinx
( )
'( ) 1
f x x
f x
( ) sin
'( ) cos
f x x
f x x
58. (iii) Prove x > sinx , for x > 0
1
y
x 2
y = x
y = sinx
( )
'( ) 1
f x x
f x
( ) sin
'( ) cos
f x x
f x x
for 0 , cos 1
2
x x
increases faster than siny x y x
sin , for 0
2
x x x
59. (iii) Prove x > sinx , for x > 0
1
y
x 2
y = x
y = sinx
( )
'( ) 1
f x x
f x
( ) sin
'( ) cos
f x x
f x x
for 0 , cos 1
2
x x
increases faster than siny x y x
sin , for 0
2
x x x
for , sin 1
2
x x
sin , for
2
x x x
60. (iii) Prove x > sinx , for x > 0
1
y
x 2
y = x
y = sinx
( )
'( ) 1
f x x
f x
( ) sin
'( ) cos
f x x
f x x
for 0 , cos 1
2
x x
increases faster than siny x y x
sin , for 0
2
x x x
for , sin 1
2
x x
sin , for
2
x x x
sin , for 0x x x
61. (iii) Prove x > sinx , for x > 0
1
y
x 2
y = x
y = sinx
( )
'( ) 1
f x x
f x
( ) sin
'( ) cos
f x x
f x x
for 0 , cos 1
2
x x
increases faster than siny x y x
sin , for 0
2
x x x
for , sin 1
2
x x
sin , for
2
x x x
sin , for 0x x x Exercise 10F