Log Trig Simplify
1. Problem 34: If $\log_2 x = \log_2 25$, find $x$.
Since logarithm base 2 of $x$ equals logarithm base 2 of 25, by the property of logarithms, the arguments must be equal:
$$x = 25$$
Answer: $x = 25$ (not among options a) 1, b) 2, c) 5, d) 3). Possibly a typo or missing option.
2. Problem 25: Simplify $\frac{\tan \theta \cot \theta}{\sec \theta}$.
Recall:
- $\tan \theta = \frac{\sin \theta}{\cos \theta}$
- $\cot \theta = \frac{\cos \theta}{\sin \theta}$
- $\sec \theta = \frac{1}{\cos \theta}$
Calculate numerator:
$$\tan \theta \cot \theta = \frac{\sin \theta}{\cos \theta} \times \frac{\cos \theta}{\sin \theta} = 1$$
Divide by denominator:
$$\frac{1}{\sec \theta} = \cos \theta$$
Answer: $\cos \theta$ (option c).
3. Problem 26: Simplify $\sin^2 \theta + \cos^2 \theta + \tan^2 \theta$.
Recall:
- $\sin^2 \theta + \cos^2 \theta = 1$
- $\tan^2 \theta = \sec^2 \theta - 1$
Substitute:
$$1 + (\sec^2 \theta - 1) = \sec^2 \theta$$
Answer: $\sec^2 \theta$ (option c).
4. Problem 27: Simplify $2 \sin^2 \theta + \cos^2 \theta + \frac{1}{\sec^2 \theta}$.
Recall:
- $\frac{1}{\sec^2 \theta} = \cos^2 \theta$
- $\sin^2 \theta + \cos^2 \theta = 1$
Rewrite:
$$2 \sin^2 \theta + \cos^2 \theta + \cos^2 \theta = 2 \sin^2 \theta + 2 \cos^2 \theta = 2(\sin^2 \theta + \cos^2 \theta) = 2 \times 1 = 2$$
Answer: 2 (option a).
5. Problem 28: Simplify $5 \sin \theta \csc \theta + 2 \cos \theta \sec \theta + 3 \tan \theta \cot \theta$.
Recall:
- $\csc \theta = \frac{1}{\sin \theta}$
- $\sec \theta = \frac{1}{\cos \theta}$
- $\tan \theta \cot \theta = 1$
Calculate each term:
$$5 \sin \theta \times \frac{1}{\sin \theta} = 5$$
$$2 \cos \theta \times \frac{1}{\cos \theta} = 2$$
$$3 \times 1 = 3$$
Sum:
$$5 + 2 + 3 = 10$$
Answer: 10 (option a).
6. Problem 29: Simplify $\sin^2 x (1 + \cot^2 x)$.
Recall:
- $1 + \cot^2 x = \csc^2 x$
- $\csc x = \frac{1}{\sin x}$
Rewrite:
$$\sin^2 x \times \csc^2 x = \sin^2 x \times \frac{1}{\sin^2 x} = 1$$
Answer: 1 (option a).
7. Problem 30: Simplify $\sec \theta - \sin \theta \tan \theta$.
Recall:
- $\sec \theta = \frac{1}{\cos \theta}$
- $\tan \theta = \frac{\sin \theta}{\cos \theta}$
Calculate second term:
$$\sin \theta \times \frac{\sin \theta}{\cos \theta} = \frac{\sin^2 \theta}{\cos \theta}$$
Rewrite expression:
$$\frac{1}{\cos \theta} - \frac{\sin^2 \theta}{\cos \theta} = \frac{1 - \sin^2 \theta}{\cos \theta}$$
Recall $1 - \sin^2 \theta = \cos^2 \theta$:
$$\frac{\cos^2 \theta}{\cos \theta} = \cos \theta$$
Answer: $\cos \theta$ (option b).
8. Problem 31: Simplify $\frac{1}{1 - \sin^2 x} - \frac{1}{1 - \cos^2 x}$.
Recall:
- $1 - \sin^2 x = \cos^2 x$
- $1 - \cos^2 x = \sin^2 x$
Rewrite:
$$\frac{1}{\cos^2 x} - \frac{1}{\sin^2 x} = \sec^2 x - \csc^2 x$$
Recall identity:
$$\csc^2 x - \cot^2 x = 1$$
But here, difference is $\sec^2 x - \csc^2 x$, no direct simplification to options.
Check options:
a) $\cot^2 \theta$
b) $\csc^2 \theta$
c) $\sec^2 \theta$
d) 1
No direct match; expression equals $\sec^2 x - \csc^2 x$.
9. Problem 32: Simplify $\frac{\sec^2 x - \tan^2 x}{1 + \tan^2 x + \cos^2 \theta}$.
Recall:
- $\sec^2 x - \tan^2 x = 1$
- $1 + \tan^2 x = \sec^2 x$
Rewrite denominator:
$$\sec^2 x + \cos^2 \theta$$
No further simplification without values.
Answer is $\frac{1}{\sec^2 x + \cos^2 \theta}$, no option matches.
10. Problem 33: Simplify $\frac{1 + \tan^2 \theta}{1 + \cot^2 \theta}$.
Recall:
- $1 + \tan^2 \theta = \sec^2 \theta$
- $1 + \cot^2 \theta = \csc^2 \theta$
Rewrite:
$$\frac{\sec^2 \theta}{\csc^2 \theta} = \sec^2 \theta \times \sin^2 \theta = \frac{1}{\cos^2 \theta} \times \sin^2 \theta = \tan^2 \theta$$
Answer: $\tan^2 \theta$ (option c).
11. Problem 34 (second): Simplify $\frac{\sin \theta \cos \theta \tan \theta + \sin \theta \cos \theta \cot \theta}{\sin \theta \sec \theta}$.
Recall:
- $\tan \theta = \frac{\sin \theta}{\cos \theta}$
- $\cot \theta = \frac{\cos \theta}{\sin \theta}$
- $\sec \theta = \frac{1}{\cos \theta}$
Calculate numerator:
$$\sin \theta \cos \theta \times \frac{\sin \theta}{\cos \theta} + \sin \theta \cos \theta \times \frac{\cos \theta}{\sin \theta} = \sin^2 \theta + \cos^2 \theta = 1$$
Calculate denominator:
$$\sin \theta \times \frac{1}{\cos \theta} = \frac{\sin \theta}{\cos \theta} = \tan \theta$$
Expression:
$$\frac{1}{\tan \theta} = \cot \theta$$
Answer: $\cot \theta$ (not among options). Possibly missing option.
Summary of answers:
34) $x=25$ (not in options)
25) $\cos \theta$ (c)
26) $\sec^2 \theta$ (c)
27) 2 (a)
28) 10 (a)
29) 1 (a)
30) $\cos \theta$ (b)
31) Expression equals $\sec^2 x - \csc^2 x$ (no direct option)
32) $\frac{1}{\sec^2 x + \cos^2 \theta}$ (no direct option)
33) $\tan^2 \theta$ (c)
34 second) $\cot \theta$ (no option)