recategorized by
543 views
1 votes
1 votes

The number of real roots of the equation $1+\cos ^2x+\cos ^3 x – \cos^4x=5$ is equal to

  1. $0$
  2. $1$
  3. $3$
  4. $4$
recategorized by

1 Answer

0 votes
0 votes
0 real roots of the equation as the maximum value cos x can take is 1 and then LHS of equation will become 2. LHS can never become 5.

Related questions

1 votes
1 votes
2 answers
2
go_editor asked Sep 13, 2018
492 views
The number of real roots of the equation $2 \cos \big(\frac{x^2+x}{6}\big)=2^x+2^{-x}$ is$0$$1$$2$$\infty$
6 votes
6 votes
3 answers
3
Arjun asked Sep 23, 2019
984 views
The number of divisors of $6000$, where $1$ and $6000$ are also considered as divisors of $6000$ is$40$$50$$60$$30$
2 votes
2 votes
2 answers
4
Arjun asked Sep 23, 2019
659 views
The sum of the series $\dfrac{1}{1.2} + \dfrac{1}{2.3}+ \cdots + \dfrac{1}{n(n+1)} + \cdots $ is$1$$1/2$$0$non-existent