Multiple choice

$\text{cosec } 69^{\circ} + \cot 69^{\circ}$, when expressed in terms of angles between $0^{\circ}$ and $45^{\circ}$, becomes

  1. $\sec 21^{\circ} + \tan 21^{\circ}$
  2. $\sin 21^{\circ} + \cot 21^{\circ}$
  3. $\sin 21^{\circ} + \cos 21^{\circ}$
  4. $\sec 21^{\circ} + \cot 21^{\circ}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Using co-function identities, cosec(69) = sec(90-69) = sec(21) and cot(69) = tan(90-69) = tan(21). Thus, cosec(69) + cot(69) = sec(21) + tan(21).

AI explanation

Using the complementary angle identities, we convert the given functions to fit the specified range. We write cosec 69 degrees as sec 21 degrees, and we write cot 69 degrees as tan 21 degrees. Substituting these into the original expression gives sec 21 degrees + tan 21 degrees.

Keep practicing — related questions