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 23 Integral with constant u-substitution 14 Given a matrix $A$ find $A^n$. 13 Prove that there are no integers $x$ and $y$ such that $3x^2=13+4y^2$ 11 $\tan(z)=i$, no solution 8 Solution to this Differential Equation $f''(x)=f(x)f'(x)$ needed

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 +25 $x^2 y''' - 3x^2 y'' + 6xy' -6y = 0$ +10 Particular solutions +10 Find the general solution for $t^2y'' -2y = t^2 -1$ +10 How to analyze the following ODE with 2 variables

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 11 Interesting way to evaluate $\int \cos^3 x\ dx$ 3 Solving only using modular arithmetic $5x+7y=1234$ [duplicate]

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