jee-advanced 2019 Q16

jee-advanced · India · paper2 Trig Graphs & Exact Values
Let $f(x) = \sin(\pi\cos x)$ and $g(x) = \cos(2\pi\sin x)$ be two functions defined for $x > 0$. Define the following sets whose elements are written in the increasing order: $$\begin{array}{ll} X = \{x : f(x) = 0\}, & Y = \{x : f'(x) = 0\} \\ Z = \{x : g(x) = 0\}, & W = \{x : g'(x) = 0\} \end{array}$$
List-I contains the sets $X$, $Y$, $Z$ and $W$. List-II contains some information regarding these sets.
List-I: (I) $X$ (II) $Y$ (III) $Z$ (IV) $W$
List-II: (P) $\supseteq \left\{\frac{\pi}{2}, \frac{3\pi}{2}, 4\pi, 7\pi\right\}$ (Q) an arithmetic progression (R) NOT an arithmetic progression (S) $\supseteq \left\{\frac{\pi}{6}, \frac{7\pi}{6}, \frac{13\pi}{6}\right\}$ (T) $\supseteq \left\{\frac{\pi}{3}, \frac{2\pi}{3}, \pi\right\}$ (U) $\supseteq \left\{\frac{\pi}{6}, \frac{3\pi}{4}\right\}$
Which of the following is the only CORRECT combination?
(A) (III), (R), (U)
(B) (IV), (P), (R), (S)
(C) (III), (P), (Q), (U)
(D) (IV), (Q), (T)
Let $f(x) = \sin(\pi\cos x)$ and $g(x) = \cos(2\pi\sin x)$ be two functions defined for $x > 0$. Define the following sets whose elements are written in the increasing order:
$$\begin{array}{ll}
X = \{x : f(x) = 0\}, & Y = \{x : f'(x) = 0\} \\
Z = \{x : g(x) = 0\}, & W = \{x : g'(x) = 0\}
\end{array}$$

List-I contains the sets $X$, $Y$, $Z$ and $W$. List-II contains some information regarding these sets.

List-I:
(I) $X$
(II) $Y$
(III) $Z$
(IV) $W$

List-II:
(P) $\supseteq \left\{\frac{\pi}{2}, \frac{3\pi}{2}, 4\pi, 7\pi\right\}$
(Q) an arithmetic progression
(R) NOT an arithmetic progression
(S) $\supseteq \left\{\frac{\pi}{6}, \frac{7\pi}{6}, \frac{13\pi}{6}\right\}$
(T) $\supseteq \left\{\frac{\pi}{3}, \frac{2\pi}{3}, \pi\right\}$
(U) $\supseteq \left\{\frac{\pi}{6}, \frac{3\pi}{4}\right\}$

Which of the following is the only CORRECT combination?

(A) (III), (R), (U)

(B) (IV), (P), (R), (S)

(C) (III), (P), (Q), (U)

(D) (IV), (Q), (T)