If \(y=f(x)\) satisfies
\[
\tan x \frac{dy}{dx}+(1+\tan^2 x)y=\tan x(1+\tan^2 x)^2
\]
and passes through \(\left(\frac{\pi}{4},\frac{3}{4}\right)\), find \(f\left(\frac{\pi}{3}\right)\)
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Convert everything into \(\sec^2 x\) when tan/sec appear together.