Indefinite Integration 3 Question 15

15. Consider the statements

P : There exists some xR such that,

f(x)+2x=2(1+x2)

Q : There exists some xR such that, 2f(x)+1=2x(1+x).

Then,

(a) both P and Q are true

(b) P is true and Q is false

(c) P is false and Q is true

(d) both P and Q are false

Show Answer

Answer:

Correct Answer: 15. (c)

Solution:

  1. Here, f(x)+2x=(1x)2sin2x+x2+2x

where, P:f(x)+2x=2(1+x)2

2(1+x2)=(1x)2sin2x+x2+2x(1x)2sin2x=x22x+2(1x)2sin2x=(1x)2+1(1x)2cos2x=1

which is never possible.

P is false.

Again, let Q:h(x)=2f(x)+12x(1+x)

where, h(0)=2f(0)+10=1

h(1)=2f(1)+14=3, as h(0)h(1)<0

h(x) must have a solution.

Q is true.



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