can someone help solve this problem?

Question

Function of a function
Let U = f(x, y)
X= rcosØ
Y= rsinØ
Show that
1.dy/dx = cosØdu/dr – sinØ/r.du/dx


du/dy=sinØdu/dr+cosØ/r.du/dØ

Answer 1

if a function depends on a variable nd tht variable again depends on other varible then we apply lebnittz rule
in this case
du/dy = (du/dr). (dr/dy) + (du/dphi).(dphi/dy)


so solve it urself

hope u got ur answer:-))

Answer 2

U have to take the derivative w.r.t x
1) dx/do= - r sino
2) dy/do= r coso

dy/dx=dy/do x do/dx

Answer 3

the answer is 44

(according to HITCH-HIKERS GUIDE TO THE GALAXY....the answer to everything is 44)