Calculate the first derivative of the following functions and say the rule that you use in each case. (20 points, 5 points each) a) y= x 2
−10
x+5
​
b) y=cos(x 3
) c) y=6x 7
⋅sin(x) d) y=99x 9
+ x
9
​
+9x+9 x
​
+9