Trig Ratios Cdc077
1. Given that $\sin \theta = \frac{5}{13}$ and $\theta$ is acute, find:
(a) $\tan \theta$
(b) $\csc \theta$
(c) $\sin \theta$
(d) $\cos \theta$
(e) $\cot \theta$
---
**Step 1: Understand the problem**
We are given $\sin \theta = \frac{5}{13}$ and $\theta$ is acute (meaning $0 < \theta < 90^\circ$).
**Step 2: Recall the Pythagorean identity and definitions**
- $\sin \theta = \frac{\text{opposite}}{\text{hypotenuse}}$
- $\cos \theta = \frac{\text{adjacent}}{\text{hypotenuse}}$
- $\tan \theta = \frac{\sin \theta}{\cos \theta} = \frac{\text{opposite}}{\text{adjacent}}$
- $\csc \theta = \frac{1}{\sin \theta}$
- $\cot \theta = \frac{1}{\tan \theta} = \frac{\cos \theta}{\sin \theta}$
**Step 3: Find $\cos \theta$ using Pythagoras**
Since $\sin \theta = \frac{5}{13}$, opposite side = 5, hypotenuse = 13.
Using Pythagoras theorem:
$$\text{adjacent} = \sqrt{13^2 - 5^2} = \sqrt{169 - 25} = \sqrt{144} = 12$$
So,
$$\cos \theta = \frac{12}{13}$$
**Step 4: Calculate each required value**
(a) $\tan \theta = \frac{\sin \theta}{\cos \theta} = \frac{5/13}{12/13} = \frac{5}{12}$
(b) $\csc \theta = \frac{1}{\sin \theta} = \frac{1}{5/13} = \frac{13}{5}$
(c) $\sin \theta = \frac{5}{13}$ (given)
(d) $\cos \theta = \frac{12}{13}$ (calculated)
(e) $\cot \theta = \frac{1}{\tan \theta} = \frac{12}{5}$
---
**Final answers:**
(a) $\tan \theta = \frac{5}{12}$
(b) $\csc \theta = \frac{13}{5}$
(c) $\sin \theta = \frac{5}{13}$
(d) $\cos \theta = \frac{12}{13}$
(e) $\cot \theta = \frac{12}{5}$