what does the polar equation r=1/(sintheta

+ costheta) represent?

how do I do this problem

In your text or in your notes you should find the following relationship between (r,Ø) and (x,y)

x = rcosØ -->cosØ = x/r
y = rsinØ --> sinØ = y/r
r^2 = x^2 + y^2
and
tanØ = y/x

so in
r = 1/(sinØ + cosØ)
r(sinØ + cosØ) = 1
rsinØ + rcosØ = 1
y+x=1 , which of course is a straight line with slope -1 and y-intercept of 1