Q39 / 60 · JEE Advanced 2014 (Paper 2) · Mathematics

let f1 :R→R, f2 :0, ∞→R, f3 :R→R and f4 :R→[0, ∞) be defined by
f1x=xifx<0exifx≥0 ;f2x=x2;f3x=sin⁡xifx<0xifx≥0 and f4x=f2f1xifx<0f2f1x-1ifx≥0
 
  List – I   List – II
(A) f4 is (P) Onto but not one – one
(B) f3 is (Q) neither continuous nor one-one
(C) f2 of f1 is (R) differentiable but not one-one
(D) f2 is (S) continuous and one-one

  • A
    a-q;b-r;c-s;d-p;
  • Correct answer
    B
    a-p;b-r;c-q;d-s;
  • C
    a-q;b-s;c-r;d-p;
  • D
    a-q;b-p;c-r;d-s;

Solution

f2f1=x2,x<0e2x,x≥0
f4:R→[0, ∞)
f4x=f2f1x,x<0f2f1x-1,x≥0
=x2,x<0e2x-1,x≥0
Figure
Figure

f2x is continuous and one-one.

Figure

f3x is differentiable but not one-one.
Figure

f2f1x is neither one one nor continuous.
Figure 

f4x is onto but not one-one.

Hence, the correct answer is option: 'B'.

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