$$4\sin\left(2x\right)-\sin\left(x\right)=0$$

$$\int\sec^{11}\left(5x\right)\tan^3\left(5x\right)dx$$

$$\ln\left(a+b\right)+4\ln\left(a-b\right)-5\ln c$$

$$-3x^2+2xy+1y^2$$

$$\frac{x^2-16}{9x-6}\cdot\frac{15x-10}{x+4}$$

$$\int\left(\frac{2y}{y^2-5}\right)dy$$

$$\frac{2}{+\infty}$$