If `y=secx+tanx` then prove that `(d^2y)/(dx^(2))=cosx/((1-sinx)^(2))`.

Explanation

To prove that \(\frac{d^2y}{dx^2} = \frac{\cos x}{(1 - \sin x)^2}\) given \(y = \sec x + \tan x\), we will follow these steps:

### Step 1: Rewrite \(y\)
Start with the given function:
\[ y = \sec x + \tan x \]
Using the definitions of secant and tangent, we can rewrite \(y\) as:
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