JEE Main2003MathematicsLimitsActual
Let f ( a )= g ( a )= k and their n th derivatives f ^ n ( a ), g ^ n ( a ) exist and are not equal for some n . Further if _ x a f(a) g(x)-f(a)-g(a) f(x)+f(a) g(x)-f(x) =4 then the value of k is
Options
- A0
- B4
- C2
- D1
Correct answer
B. 4
Step-by-step solution
_ x a k 9(x)-k f(x) 9(k)-f(x) =4 (By L'Hospital rule) _ x a k 9^ (x)-f^ (x) 9^ (x)-f^ (x) =4 or k=4