NTA Abhyas JEE Main2020MathematicsLimitsPractice
The value of lim x → 0 log ( 1 + x + x 2 ) + log ( 1 − x + x 2 ) sec x − cos x is equal to
Options
- A− 1
- B1
- C0
- D2
Correct answer
B. 1
Step-by-step solution
lim x → 0 log 1 + x + x 2 + log 1 - x + x 2 sec x - cos x = lim x → 0 log 1 + x 2 2 - x 2 1 - cos 2 x / cos x = lim x → 0 log 1 + x 2 + x 4 sin x tan x = lim x → 0 log 1 + x 2 1 + x 2 x 2 1 + x 2 · x 2 1 + x 2 · 1 sin x x · tan x x · x 2 = 1 as lim x → 0 log 1 + x x = 1