JEE Advanced (Matrix Match): Trigonometric Functions & Equations
DIRECTIONS (Q. 1): Each question contains statements given in two columns, which have to be matched. The statements in Column-I are labelled A, B, C and D, while the statements in Column-II are labelled p, q, r, s and t. Any given statement in Column-I can have correct matching with ONE OR MORE statement(s) in Column-II. The appropriate bubbles corresponding to the answers to these questions have to be darkened as illustrated in the following example :
If the correct matches are A-p, s and t; B-q and r; C-p and q; and D-s then the correct darkening of bubbles will look like the given.
Q. 1.
In this questions there are entries in columns 1 and 2. Each entry in column 1 is related to exactly one entry in column 2. Write the correct letter from column 2 against the entry number in column 1 in your answer book.
(1992 - 2 Marks)
Ans.
Sol.
⇒ 3α ∈ II quad and 2α ∈ II quad ⇒ sin 3α = + ve
cos 2α = - ve 
∴ (B) corresponds to (p).
⇒ 3α ∈ II or III quad and 2α ∈ II quad
⇒ Nothing can be said about the sign of 
over this interval.
⇒ 3α ∈ III quad and 2α ∈ II quad
⇒ sin 3α = - ve, cos 2α = - ve 
∴ (A) corresponds to (r)
If a ∈(0,π/ 2)
⇒ Nothing can be said about the sign of 
over the given interval.
