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Query

Neha Gupta
31 posts

Guys, should it be a or c?
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Re: Query

Asd1995
286 posts
(a), because inverse of a function is basically its mirror image in the line y=x. So only way mirror images coincide is if they are at 0 distance from the mirror i.e they lie on y=x
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Re: Query

Neha Gupta
31 posts
yes, exactly, i am also getting this only, but see:



This answer is given.. not getting that..
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Re: Query

Econ17
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Re: Query

Asd1995
286 posts
In reply to this post by Neha Gupta
My bad, they may not necessarily intersect there. Counter example would be f(x)=-x^3 and g(x)=-(x)^1/3, which intersect at (-1,1) and (1,-1) so (c) is correct. For the points to lie on y=x the function has to be strictly increasing.
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Re: Query

Econ17
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Re: Query

Asd1995
286 posts
In reply to this post by Econ17
The question is IF, they intersect, they'd do it on y=x. This is not necessarily correct though.
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Re: Query

Econ17
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Re: Query

Neha Gupta
31 posts
In reply to this post by Asd1995
Ok thanks:)
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Re: Query

Gin_no
12 posts
In reply to this post by Econ17
Correct answer is (A) ?
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Re: Query

Neha Gupta
31 posts
its C
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Re: Query

Gin_no
12 posts
This post was updated on Jun 26, 2017; 6:03pm.
According to your solution they are not intersection point, P(α, β) and Q(β,α) intersect only if they are same point's coordinate because they are intersection point of f and inv f. So α = β and slope of a single point is undefined.

If P(a,b) and Q(c,d) are two different intersection point of f and inv f then should lie on y = x. and
slope of PQ will be 1.

Do lnx and e^x intersect each-other? how and where ?