JEE Advanced2015MathematicsLimitsActual
Let m and n be two positive integers greater than 1. If lim α → 0 ⁡ e c o s ⁡ ( α n ) - e α m = - e 2 then the value of m n is
Correct answer
0
Step-by-step solution
lim α → 0 e cos α n - e α m = - e 2 ⇒ Using L'Hospital's Rule lim α → 0 e cos α n ⋅ - sin α n ⋅ n α n - 1 m ⋅ α m - 1 = - e 2 ⇒ m n = 2 .