The GATE Grind

GATE 2019 AE – Question 41

Engineering Mathematics · Calculus: Limits, continuity, differentiability, chain rule, maxima and minima, integration · 2 marks · Numerical answer

How many points of intersection do y=x and y=cos x have?

Practise this question in The GATE Grind →

Show answer and explanation

Correct answer: 1 to 1

Explanation

Intersections satisfy g(x)=x−cos x=0. Any root lies in [−1,1]. On that interval $g\prime=1+\sin x>0$, so there is at most one root. Since g(0)=−1 and g(1)>0, continuity ensures one root. Therefore the count is 1.

More Calculus: Limits, continuity, differentiability, chain rule, maxima and minima, integration questions

All Calculus: Limits, continuity, differentiability, chain rule, maxima and minima, integration questions →