$\left(70-2\right)\left(71+1\right)$

$y^{1-1}$

$\lim_{x\to-1}\:\frac{1\:+\sqrt[3]{x}}{1+\:\sqrt[5]{x}}$

$sin^4x=cos^4$

$\lim_{x\to0}\left(\frac{\sin\left(x\right)-\sin\left(2x\right)}{x-\sin\left(x\right)}\right)$

$\sec x-\sec\:\:x\:\sec\:^{\left(2\right)}x=\tan\left(x\right)$

$\sin^2a+\cos a+1=0$