Prove that

[tex]\[ \left(3 - 4 \sin^2 x\right)\left(\sec^2 x - 4 \tan^2 x\right) = \frac{3 - \tan^2 x}{1 - 4 \sin^2 x} \][/tex]



Answer :

To address the given problem, we will verify the equation step by step.

Let's consider the equation:
[tex]\[\left(3 - 4 \sin^2 x\right)\left(\sec^2 x - 4 \tan^2 x\right) = \frac{3 - \tan^2 x}{1 - 4 \sin^2 x}\][/tex]

### Step 1: Simplify the Left-hand Side (LHS)

First, let's rewrite the left-hand side:
[tex]\[ \left(3 - 4 \sin^2 x\right) \left(\sec^2 x - 4 \tan^2 x\right) \][/tex]

We know that:
[tex]\[\sec^2 x = 1 + \tan^2 x\][/tex]

So replace [tex]\(\sec^2 x\)[/tex]:
[tex]\[ \left(3 - 4 \sin^2 x\right) \left((1 + \tan^2 x) - 4 \tan^2 x\right) \][/tex]
[tex]\[ \left(3 - 4 \sin^2 x\right) \left(1 + \tan^2 x - 4 \tan^2 x\right) \][/tex]
[tex]\[ \left(3 - 4 \sin^2 x\right) \left(1 - 3 \tan^2 x\right) \][/tex]

### Simplified LHS:
[tex]\[ (3 - 4 \sin^2 x) (1 - 3 \tan^2 x ) \][/tex]

### Step 2: Simplify the Right-hand Side (RHS)

Now consider the right-hand side:
[tex]\[ \frac{3 - \tan^2 x}{1 - 4 \sin^2 x} \][/tex]

### Step 3: Compare the Simplified LHS and RHS

We now have:
- LHS: [tex]\((4 \sin^2 x - 3) \cdot (3 \tan^2 x - 1)\)[/tex]
- RHS: [tex]\(\frac{3 - \tan^2 x}{1 - 4 \sin^2 x} \)[/tex]

From the comparison:
- LHS involves polynomial products, [tex]\((4 \sin^2 x - 3) \cdot (3 \tan^2 x - 1)\)[/tex]
- RHS involves fraction of polynomials, [tex]\(\frac{(3-\tan^2 x)}{(4 \sin^2 x - 1)}\)[/tex]

Since polynomial and fraction involve complex trigonometric functions and their identities, upon reducing, we notice that:

The expressions [tex]\( \left(4 \sin^2 x - 3\right) (3 \tan^2 x - 1) \)[/tex] do not simplify to [tex]\( \frac{3 - \tan^2 x}{1 - 4 \sin^2 x} \)[/tex]

### Conclusion:

Thus, the initial given equation turns out to be false as:
\[
\left(3 - 4 \sin^2 x\right)\left(\sec^2 x - 4 \tan^2 x\right) \neq \frac{\left(3 - \tan^2 x\right)}{\left(1 - 4 \sin^2 x\right)}