Q.

If the area of the region {(x,y):1+x2ymin {x+7,113x}} is A, then 3A is equal to          [2025]

1 47  
2 49  
3 50  
4 46  

Ans.

(3)

A=21(x+7x21)dx+12(113xx21)dx

=[x22+6xx33]21+[10x3x22x33]12

=503  3A=50.