Differentiate each of the following functions.

1. $y=2^{3x^2−x}+6x^{−0.4}$ 

   Hint (a):

   Chain Rule

2. $y=6x\ln(−3y)−x^{6^2}$ 

   Hint (b):

   Implicit differentiation.

3. $y = \frac{3}{7}\cos(11^{0.2x})$ 

   Hint (c):

   Chain Rule