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设 $f(x)=\int_0^x \cos (x-t)^2 \mathrm{~d} t, \varphi(x)=\left\{\begin{array}{ll}\frac{x-\sin x}{x-\ln (1+x)}, & x \neq 0 \\ 0, & x=0\end{array}\right.$ ，求 $\left.\frac{\mathrm{d}}{\mathrm{d} x} f(\varphi(x))\right|_{x=0}$
                        
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