Question

Using four values of $\theta$ satisfying the equation $8 \cos ^4 \theta+15 \cos ^2 \theta-2=0$ in the interval $(0,4 \pi)$, an arithmetic progression is formed, then:

• A. The common difference of A.P. may be $\pi$.
• B. The common difference of A.P. may be $2 \pi$.
• C. Two such different A.P. can be formed.
• D. Four such different A.P. can be formed.

Answer 1

Answer: (A), (D)

Correct answer is (a) The common difference of A.P. may be $\pi$.Correct answer is (d) Four such different A.P. can be formed.