Answer :

To determine if the given trigonometric identity [tex]\(\frac{1+\sin \theta - \cos \theta}{1+\sin \theta + \cos \theta} = \tan \frac{\theta}{2}\)[/tex] holds true, we need to verify both sides step by step.

Let's assign:
[tex]\[ \text{Left side} = \frac{1 + \sin \theta - \cos \theta}{1 + \sin \theta + \cos \theta} \][/tex]
[tex]\[ \text{Right side} = \tan \frac{\theta}{2} \][/tex]

First, we analyze the left side:
[tex]\[ \frac{1 + \sin \theta - \cos \theta}{1 + \sin \theta + \cos \theta} \][/tex]

To simplify the left side, let's use the following trigonometric identities and transformations:
1. Sine and Cosine Compound Angles:
Use the identity for compound angles to transform our expression:
[tex]\[ \sin \theta = \sin\left(\theta\right) \][/tex]
[tex]\[ \cos \theta = \cos\left(\theta\right) \][/tex]

2. Using the Transformation:
We can express [tex]\(\theta\)[/tex] in terms of [tex]\(\frac{\theta}{2}\)[/tex] which leads us to more convenient forms using double-angle formulas:
[tex]\[ \sin \theta = 2 \sin \frac{\theta}{2} \cos \frac{\theta}{2} \][/tex]
[tex]\[ \cos \theta = \cos^2 \frac{\theta}{2} - \sin^2 \frac{\theta}{2} \][/tex]

However, a more effective route to simplify this expression is by using sum-to-product identities and trigonometric properties altogether.

We arrive at the simplified form of the left side:
[tex]\[ \frac{1 + \sin \theta - \cos \theta}{1 + \sin \theta + \cos \theta} = \frac{(-\sqrt{2}) \cos \left(\theta + \frac{\pi}{4}\right) + 1}{(\sqrt{2}) \sin \left(\theta + \frac{\pi}{4}\right) + 1} \][/tex]

Now, consider the right side:
[tex]\[ \tan \frac{\theta}{2} \][/tex]

To check for equivalence, we analyze whether:
[tex]\[ \frac{-\sqrt{2} \cos \left(\theta + \frac{\pi}{4}\right) + 1}{\sqrt{2} \sin \left(\theta + \frac{\pi}{4}\right) + 1} \overset{?}{=} \tan \frac{\theta}{2} \][/tex]

To determine if the numerator and the denominator simplify in a manner that equals the right side, we observe from our derived forms:
[tex]\[ \frac{-\sqrt{2} \cos \left(\theta + \frac{\pi}{4}\right) + 1}{\sqrt{2} \sin \left(\theta + \frac{\pi}{4}\right) + 1} \][/tex]

Both simplified forms show that the two expressions do not simplify to exactly the same form. Therefore, upon further evaluation, we realize:

[tex]\[ \frac{1 + \sin \theta - \cos \theta}{1 + \sin \theta + \cos \theta} \neq \tan \frac{\theta}{2} \][/tex]

Thus, the given trigonometric identity does not hold true and the correct answer is:

[tex]\[ \boxed{\text{False}} \][/tex]

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