Find $\frac { d y } { d x }$ for each of the following functions.

1. $y = 2^{3x^2−x} + 6x^{−0.4}$

   Hint (a):

   Chain Rule

2. $y = 6x\operatorname{ln}(−3y) − x^{6^2}$

   Hint (b):

   Implicit differentiation.

3. $y =\frac { 3 } { 7 }\operatorname{cos}(11^{0.2x})$

   Hint (c):

   Chain Rule