CONTINUITY

TYPE IV

Discuss the continuity of the function at a given point / on it’s domain / on the given interval.

1.f(x) = 3x – 4 for 0  x  2at pt

= 2x – 42 < x  5x = 2

2.f(x) = x2 – 2 for, 2  x  4at

= 2x + 64 < x  6x = 4

3.f(x) = 0  x  3at,

= 4x – 53 < x  6x = 3

4.f(x) = 0  x  4at

= 4 < x  6x = 4

5.f(x) = x2 + 4 0 x  2 on its domain

= 3x + 22 < x  4

= x + 14 < x  6

6.f(x) =0 < x  3on it’s domain

= 3x – 13 <x  5

= 5 < x 7

7.f(x) = 0  x  2

= 3x – 12 < x  4on it’s domain

= 4 < x  6

8.f(x) = sin x 0 < x on the interral

= tan x < x 3 (0, )

= cos x 3 < x 

Type – V

Find the value k / a, b / , If the given function is continuous at a given point / on it’s domain / on its interral.

1. f(x) = 5x + 10x  1at, x = 1

= 3x + k1 < x  2

2. f(x) = 3x - 40  x  2at, x = 2

= 2x - k2 < x  4

3. f(x) = x > 0at, x = 0

x < 0

= x + 4 + bx = 0

= 1

4.f(x) = x2 + a x > 0at, x = 0

= x < 0

given f(x) = 2, find a, b.

5.f(x) = x > 0at, x = 0 find (a + b)

= x + 4 – bx < 0

6.f(x) = - 2 x  0

= 2x + 10 < x  1is continuous

= 2b 1 < x  2on (-2, 2)

7.f(x) = x2 + ax + b0 x  2is continuous

= 3x + 22 < x  4on (0, 6)

= 2ax + 5b4 < x  6

8.f(x) = 5b – 3a x -4  x  - 2is continuous

= 4x – 1-2 < x  2on [-4, 4]

= ax2 + 17b2 < x  4

9.f(x) = -2 sin x -  x - / 2is continuous

= sin x + -  / 2 < x  / 2on

= cos x /2 < x (-, )

Discuss the continuity of the function for all real ralues of x.

1.f(x) = on the interval (0, 6)

2.f(x) = on the interval (0, 6)

DERIVATIVE

Defn. –

If , = f(x) is a function of x then the derivative of with respect to ‘x’ denoted by OR f(x) is given by –

Question.

Q.Find the derivatives of the following from the 1st principle.

1)xn2) 2x2 + 33) 4x + 54) 5) 6) 7) 8) 9) 10) 11)

12)13) 14)sin x 15) cos x 16) tan x 17) cot x 18) sec x 19) cosec x 20) sin 2x 21) cos 3x 22) 23)

24) x sin x 25) x cos x 26) x2 sin x 27) x2 cos x28) ex29) e2x + 330) ax 31)72x+ 3 32) log x 33) log (4x + 5) 34) log ax

35) log10(4x + 5)

Standard Formulae :-

1.2.

3.4.

5.6.

7.8.

9.10.

11.12.

13.14.

15.16.

17.18.

19.20.

Derivative of composite function.

Thm. –

Statement :- If ‘’ is a differentiable function of ‘u’ & ‘u’ is a differentiable function. of ‘x’ then prove that,

Proof :-

Let x be the small increment in x, the corrousponding inctements in u are u respectively.

As x  0, , u  0

Since,

 is a differentiable function of u  u is a differentiable function x.

we have,

taking limit as x  0

as x  0 u  0

Here, the limit of R.H.S exists, hence, the limit of R.H.S. exists

Q.Find If,

1)  = (4x2 + 3)7= 7(4x+2 + 3)6 (8x)

2)  = (tan x + 3)4= 4 (tan x + 3)3(sec2x)

3)  = (3x2 + 4)8= 8 (3x2+ 4)7(6x)

4)  =(sin x + 4)8 =8 (sin x + 4)7(cos x)

5) = (log x + 3)7= 7(log x + 3)6

6)  =

7)  = (sin x)3= 3 (sin x)2(cos x)

8) = (cos x)3= 3 (cos x)2(-sin x)

9)  = (tan x)3= 3 (tan x)2(sec2 x)

10)  = sec3 x = 3 sec2 x. sec x tan x

11)  = (4x2 + 3x + 7)8 = 8 (4x2 + 3x + 7)7(8x + 3)

12) = =

13)  = =

14)  = =

15) = =

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