Some Useful Expansio
1. Right hand and Left hand Limit (i) sin x = x –
x3
+
x
3! 5
x2 x
To evaluate lim f x (ii) cos x = 1 –
2!
+
4
x a
3
2
1. Put x = a + h in f (x) to get lim f a h (iii) tan x = x + x +
h0 3 15
(iv) sin–1 x = x
2. Take the limit as h → 0.
12. x 3 12. 32 5
To evaluate lim f x . +
3!
+
5!
X +
x a
1. Put x = a – h in f (x) to get lim f a h .
h0
(v) (sin–1 x)²
2. Take the limit as h → 0.
2 2.22 4
= x² + x
2! 4!
2. Some Useful Limits (vi) tan–1 x = x –
x3
3
+
(4) Exponential and Logar
x n an
(1) lim = nan – 1, where n ∈ Q, the set of rational numbers.
x a x a ex 1
(i) lim =1
x 0 x
(2)
ax 1
(ii) lim = loge a
x 0 x
, if a 1 ax bx
n (iii) lim = loge
(i) lim a = 1, if a 1 x 0 x
n
0, if 1 a 1
1 x
n
doesnot exist , if a 1 1
(iv) lim =n
x 0 x
a0 x p a1 x p 1 ap 1 x ap n
(ii) lim 1
x q
b0 x b1 x q1
bq 1 x bq (v) lim 1 + = e
n→0 n
1/h
a0 (vi) lim 1 ah =ea
, if p q h0
b0
log x