Answer :

Certainly! Let's go through the problem step by step.

We are given the expression:
[tex]\[ \tan \theta \cdot (1 - \tan \theta) \cdot (1 + \tan^2 \theta) \][/tex]

Let's denote [tex]\(\tan \theta\)[/tex] by [tex]\( t \)[/tex] for simplicity. So the expression becomes:
[tex]\[ t \cdot (1 - t) \cdot (1 + t^2) \][/tex]

Now, we'll simplify the expression step by step.

1. First, consider [tex]\( t \cdot (1 - t) \)[/tex]:
[tex]\[ t \cdot (1 - t) = t - t^2 \][/tex]

2. Next, multiply the result by [tex]\( (1 + t^2) \)[/tex]:
[tex]\[ (t - t^2) \cdot (1 + t^2) \][/tex]

Let's distribute each term in [tex]\( (t - t^2) \)[/tex] through the [tex]\( (1 + t^2) \)[/tex]:

3. Distribute the [tex]\( t \)[/tex] term:
[tex]\[ t \cdot (1 + t^2) = t \cdot 1 + t \cdot t^2 = t + t^3 \][/tex]

4. Distribute the [tex]\( -t^2 \)[/tex] term:
[tex]\[ -t^2 \cdot (1 + t^2) = -t^2 \cdot 1 + -t^2 \cdot t^2 = -t^2 - t^4 \][/tex]

5. Combine all the distributed terms:
[tex]\[ t + t^3 - t^2 - t^4 \][/tex]

Thus, the simplified expression for:
[tex]\[ \tan \theta \cdot (1 - \tan \theta) \cdot (1 + \tan^2 \theta) \][/tex]
is:
[tex]\[ t (1 - t) (1 + t^2) = t \cdot (1 - t) \cdot (1 + t^2) = t (1 - t) (t^2 + 1) \][/tex]

So, our final expression is:
[tex]\[ t (1 - t) (t^2 + 1) \][/tex]