If cot⁴θ + cot²θ = 2.2, then csc⁴θ − csc²θ = ?
- 0
- 1.1
- 2.2
- 3.3
Show answer and solution
Correct answer: C. 2.2
1. Use csc²θ = 1 + cot²θ.
2. csc⁴θ − csc²θ = csc²θ(csc²θ − 1) = (1 + cot²θ)(cot²θ).
3. Expanding: cot²θ + cot⁴θ = cot⁴θ + cot²θ = 2.2.
_Source: RRB Group D CEN-02/2018 PYQ, Q.10._