Use app×
Join Bloom Tuition
One on One Online Tuition
JEE MAIN 2025 Foundation Course
NEET 2025 Foundation Course
CLASS 12 FOUNDATION COURSE
CLASS 10 FOUNDATION COURSE
CLASS 9 FOUNDATION COURSE
CLASS 8 FOUNDATION COURSE
0 votes
3.9k views
in Mathematics by (97.5k points)
closed by
If `g(x)=max(y^(2)-xy)(0le yle1)`, then the minimum value of g(x) (for real x) is
A. `(1)/(4)`
B. `3-sqrt3`
C. `3+sqrt8`
D. `(1)/(2)`

1 Answer

0 votes
by (94.7k points)
selected by
 
Best answer
Correct Answer - B
`y^(2)-xy=(y-(x)/(2))^(2)-(x^(2))/(4) rArr y^(2)-xy` is decreasing for `yle (x)/(2)` and increasing for `yge(x)/(2)`
Thus the largest value of `y^(2)-xy` must be at `y=0,(x)/(2)` or 1.
The values are `0,(x^(2))/(4),1-x` for `x in (0,1)`
And for `x in (0,1)g(x)=max((x^(2))/(4),1-x)`
Also `x^(2)+4x=4=0 rArr x = -2 pm sqrt8`
`rArr" "g(x)=1-x " for "x le sqrt8-2 and (x^(2))/(4)` for `x ge sqrt8-2`
`rArr" g(x) is minimum at "x=sqrt8-2` and minimum value is `3-sqrt8`

Welcome to Sarthaks eConnect: A unique platform where students can interact with teachers/experts/students to get solutions to their queries. Students (upto class 10+2) preparing for All Government Exams, CBSE Board Exam, ICSE Board Exam, State Board Exam, JEE (Mains+Advance) and NEET can ask questions from any subject and get quick answers by subject teachers/ experts/mentors/students.

Categories

...