tolong jawabkan no 19&20 beserta caranya

19) f(x) = 2x^2/3 - 6x . x^1/2
= 2x^(2/3) - 6x^(3/2)
f'(x) = 2(2/3) x^(2/3 - 1) - 6(3/2) x^(3/2 - 1)
= 4/3 x^(-1/3) - 9x^(1/2)
f'(1) = 4/3 (1)^(-1/3) - 9(1)^(1/2) = 4/3 - 9 = (4 - 27)/3 = -23/3

20) C = A . B^t
= (1 ... 0) (-2 ... 1)
.. (2 .. 2) (-3 ... 1)

= (-2 + 0 ... 1 + 0)
.. (-4 - 6 .... 2 + 2)

= (-2 .... 1)
.. (-10 .. 4)

C^-1 = 1/(-8 - (-10)) (4 .... -1) = 1/2 (4 ..... -1) = (2 ... -1/2)
................................ (10 .. -2) ........ (10 .. -2) .. (5 ..... -1)