Guys, we have discussed the slope of the tangent line and also the related rates yesterday and I'am in a trouble..I can't even understand these topics even though my Professor gave already a bunch of example.. I tried solving problems related to these topics and It's hard for me to get the correct answer..

Can you answer these problems which I found on my book and "Please" tell me how you got the answer step by step..Pls.. Thanks in advance guys!

*Slope of the Tangent Line

Find the slope of the tangent line and write an equation of the tangent line to the graph of the equation at the given point P.

x^2y+sin y=2pi at P(1,2pi)

*Related Rates

a.) The Area(A) of an equilateral triangle is decreasing at a rate(dA/dt) of 4cm^2/min. Find the rate(dl/dt) at which the length(l) is charging when its area is 200cm^2

b.) Gas is escaping from a spherical balloon at a rate dV/dt=10ft^3/hr.At what rate(dr/dt) is the radius(r) changing when the volume V=400ft^3