JAMIA 2021 — Mathematics PYQ
JAMIA | Mathematics | 2021The minimum value of 4x+4,1−x, x∈R, is
Choose the correct answer:
- A.
2
- B.
4
(Correct Answer) - C.
1
- D.
0
4
Explanation
1. Identify the Terms
Let:
-
a=4x
-
b=41−x
Both terms are always positive for any x∈R.
2. Apply AM-GM Inequality
24x+41−x≥4x⋅41−x
3. Simplify the Geometric Mean
Inside the square root, use the property am⋅an=am+n:
4x+1−x=41
4=2
4. Solve for the Minimum Value
Substitute back into the inequality:
24x+41−x≥2
4x+41−x≥2⋅2
4x+41−x≥4
Final Result
The minimum value of 4x+41−x is 4.
Explanation
1. Identify the Terms
Let:
-
a=4x
-
b=41−x
Both terms are always positive for any x∈R.
2. Apply AM-GM Inequality
24x+41−x≥4x⋅41−x
3. Simplify the Geometric Mean
Inside the square root, use the property am⋅an=am+n:
4x+1−x=41
4=2
4. Solve for the Minimum Value
Substitute back into the inequality:
24x+41−x≥2
4x+41−x≥2⋅2
4x+41−x≥4
Final Result
The minimum value of 4x+41−x is 4.

