Find the derivative of f (x) from the first principles, where f(x) is(i) `s in x + cos x` (ii) `x s in x`

Explanation

To find the derivative of the given functions \( f(x) = \sin x + \cos x \) and \( f(x) = x \sin x \) from first principles, we will use the definition of the derivative:

\[ f'(x) = \lim_{h \to 0} \frac{f(x+h) - f(x)}{h} \]

### Part (i): \( f(x) = \sin x + \cos x \)

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