KVPY2020MathematicsApplication of Derivatives
The maximum value of the function f ( x ) = e x + x ln x on the interval 1 ≤ x ≤ 2 is
Options
- Ae 2 + ln 2 + 1
- Be 2 + 2 ln 2
- Ce π / 2 + π 2 ln π 2
- De 3 / 2 + 3 2 ln 3 2
Correct answer
B. e 2 + 2 ln 2
Step-by-step solution
f ' ( x ) = e x + 1 + ln x > 0 ( as   x ∈ [ 1 , 2 ] ) ⇒ f ( x ) increases in [ 1 , 2 ] ⇒ f max = f ( 2 ) = e 2 + 2 ℓ n 2