$\frac{\cos\left(90^{\circ}-a\right)}{\sena}$

$-4x^3+10x^2-6$

$\cos\left(1.96\right)$

$\frac{\left(x+y\right)^6-6\left(x^6+y^6\right)}{\left(xy\right)^3}$

$3\sqrt{14a}-5\sqrt{35a^2}$

$\left(5a^2-12\right)\left(5a^2+12\right)$

$sin\left(t\right)tan\left(t\right)=\frac{1-cos^2t}{cos\:t}$