JEE Main202224 Jun 2022Morning ShiftMathematicsApplication of DerivativesActual
The sum of absolute maximum and absolute minimum values of the function f x = 2 x 2 + 3 x - 2 + sin x cos x in the interval 0 , 1 is
Options
- A3 + sin 1 cos 2 1 2 2
- B3 + 1 2 1 + 2 cos 1 sin 1
- C5 + 1 2 sin 1 + sin 2
- D2 + sin 1 2 cos 1 2
Correct answer
B. 3 + 1 2 1 + 2 cos 1 sin 1
Step-by-step solution
Given f x = 2 x 2 + 3 x - 2 + sin x cos x ⇒ f x = 2 x - 1 x + 2 + sin x cos x Now, f ' x = 4 x + 3 + cos 2 x 4 , 1 2 < x < 1 - 4 x + 3 + cos 2 x 4 , 0 ≤ x < 1 2 For 0 ≤ x < 1 2 ⇒ f ' x < 0 For 1 2 < x ≤ 1 ⇒ f ' x > 0 So f x has minima at x = 1 2 and maxima at x = 1 Hence, f 1 2 + f 1 = 3 + 1 2 1 + 2 cos 1 sin 1