Question

If sin theta= - 5/7, which of the following are possible?

Answer 1

Answer:

$\large\boxed{\sec\theta=\dfrac{7}{\sqrt{24}},\ and\ \tan\theta=-\dfrac{5}{\sqrt{24}}}\\\boxed{\cos\theta=\dfrac{\sqrt{24}}{7},\ and\ \tan\theta=\dfrac{5}{\sqrt{24}}}$

Step-by-step explanation:

$\text{Use:}\\\\\sin^2\theta+\cos^2\theta=1\to\cos\theta=\pm\sqrt{1-\sin^2\theta}\\\\\tan\theta=\dfrac{\sin\theta}{\cos\theta}\\\\\sec\theta=\dfrac{1}{\cos\theta}\\\\==========================\\\\\sin\theta=-\dfrac{5}{7}\\\\\cos\theta=\pm\sqrt{1-\left(-\frac{5}{7}\right)^2}=\pm\sqrt{1-\frac{25}{49}}=\pm\sqrt{\frac{24}{49}}=\pm\dfrac{\sqrt{24}}{\sqrt{49}}=\pm\dfrac{\sqrt{24}}{7}\\\\\sec\theta=\pm\dfrac{1}{\frac{\sqrt{24}}{7}}=\pm\dfrac{7}{\sqrt{24}}$

$\tan\theta=\pm\dfrac{-\frac{5}{7}}{\frac{\sqrt{24}}{7}}=\mp\dfrac{5}{7\!\!\!\!\diagup_1}\cdot\dfrac{7\!\!\!\!\diagup^1}{\sqrt{24}}=\mp\dfrac{5}{\sqrt{24}}$

$\sin\theta=-\dfrac{5}{7}$