GateAI
Calculus

GATE CSE 2015 Set 1 · Q5

MCQ1 markEasy

Time

If g(x)=1−xg(x) = 1-x and h(x)=xx−1h(x) = \frac{x}{x-1}, then g(h(x))h(g(x))\frac{g(h(x))}{h(g(x))} is:

Select one answerSingle correct

Pick an option to check

Solution

Step-by-step verified solution

Official answer: A) (h(x))/(g(x))

Calculus

Given:

g(x)=1−xg(x) = 1 - x
h(x)=xx−1h(x) = \frac{x}{x - 1}

First, find $g(h(x))$:

g(h(x))=1−h(x)=1−xx−1=x−1−xx−1=−1x−1=11−xg(h(x)) = 1 - h(x) = 1 - \frac{x}{x - 1} = \frac{x - 1 - x}{x - 1} = \frac{-1}{x - 1} = \frac{1}{1 - x}

Next, find $h(g(x))$:

h(g(x))=g(x)g(x)−1=1−x(1−x)−1=1−x−x=x−1xh(g(x)) = \frac{g(x)}{g(x) - 1} = \frac{1 - x}{(1 - x) - 1} = \frac{1 - x}{-x} = \frac{x - 1}{x}

Now, compute the ratio:

g(h(x))h(g(x))=−1x−1x−1x=−x(x−1)2\frac{g(h(x))}{h(g(x))} = \frac{\frac{-1}{x - 1}}{\frac{x - 1}{x}} = \frac{-x}{(x - 1)^2}

Let us evaluate the options:

  • Option (A): h(x)g(x)=xx−11−x=x−(x−1)2=−x(x−1)2\frac{h(x)}{g(x)} = \frac{\frac{x}{x-1}}{1-x} = \frac{x}{-(x-1)^2} = \frac{-x}{(x-1)^2}

This matches our computed ratio. Therefore, the correct option is (A).

Try the question first, then check your work.

Think the official key or this write-up is wrong?

Report error or challenge

Examiner trap

The misconception this question tests

This Calculus previous year question is Q5 of the GATE CSE 2015 Set 1 paper. Find more GATE CSE PYQs on Calculus in Engineering Mathematics, or browse all GATE CSE PYQs.

Free diagnostic

Where do you stand for GATE?

Take the 20-minute diagnostic: the 3 topics that cost you the most marks, and a rank range. Or sit 5 related Calculus PYQs now with no account.

One GATE CSE PYQ every morning

An official question by email at 7 AM IST, with a link to its verified solution. Unsubscribe in one click.

Calculus in GATE CSE

Calculus has 40 GATE CSE PYQs across 25 papers from 2011 to 2026. 14 of them are 1-mark MCQs like this one, and GATE CSE 2015 Set 1 has 4.

How GATE tests Calculus

More from GATE CSE 2015 Set 1

Share this solution

A plain-text card for WhatsApp or Telegram study groups.

GateAI solution cardGATE CSE 2015 Set 1 · Q5 · MCQ

If g(x) = 1-x and h(x) = (x)/(x-1), then (g(h(x)))/(h(g(x))) is:

Topic-wise GATE CS PYQs with verified steps

Independent practice explanation verified by the GateAI team. GATE is conducted by the IITs; question text follows the official paper.