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### Questions (42)

 6 Find the nature of the roots of the equation $6x^4-25x^3+81x^2-9x-13=0$ using Descartes's rule of signs 4 Sum to n terms the series $\cos \theta+ 2\cos 2\theta+ \cdots + n\cos n\theta$ 3 Find $\lim_{(x,y)\rightarrow (0,0)}\frac{\sin (xy)}{x+y}$ 3 proof by Mathematical induction related with geometry 3 Show that the solid generated by the revolution of the region has finite volume but infinite surface area

### Reputation (1,924)

 +2 Fourier Transform $f(x) = \frac{x}{(x^2 + a^2)}$ +2 Curve fitting exponential function +2 Fit sum of exponentials +2 Integrating $\int(\sin(\log x) + \cos(\log x)) dx$

 8 Limit $\lim_{x\to \infty}\frac{3x-\cos(2x)}{4x+\sin x}$ 8 How to find the antiderivative of the $\sqrt{4-x^2}$? 5 Question involving de Moivre identity and writing $\cos4\theta$ in terms of complex numbers 4 relearning something in mathematics? 4 Find the volume of the solid within the sphere $x^2+y^2+z^2=9$, outside the cone $z=\sqrt{x^2+y^2}$, and above the $xy$-plane.

### Tags (95)

 9 limits × 3 5 calculus × 10 8 indefinite-integrals 5 probability × 3 6 multivariable-calculus × 7 5 integration × 2 6 ordinary-differential-equations × 5 4 soft-question × 2 6 complex-numbers × 5 4 learning