Practicing Success
If $\tan (11 \theta) = \cot (7 \theta)$, then what is the value of $\sin^2 (6 \theta) + \sec^2 (9 \theta) + cosec^2 (12 \theta)$? |
$\frac{35}{12}$ $\frac{23}{6}$ $\frac{31}{12}$ $\frac{43}{12}$ |
$\frac{43}{12}$ |
tan (11θ) = cot (7θ) { we know, If tan A = cot B then A + B = 90º } So, 11θ + 7θ = 90º 18θ = 90º θ = 5º Now, sin² (6θ) + sec² (9θ) + cosec² (12θ) = sin² ( 30º ) + sec² ( 45º ) + cosec² ( 60º ) = \(\frac{1}{4}\) + 2 + \(\frac{4}{3}\) = \(\frac{ 3 + 24 + 16}{12}\) = \(\frac{ 43}{12}\) |