given the instructions tofind the following if i am given that sinx=3/5 while cosx<0 and tanr=-8/15 while sinr>0(x and r being general variables...)

a. cosx

b. sec (r)

c. sin (x-pi)

d. tan (-r)

I have absolutley no idea how to go about this problem and it would be very helpful is someone could help me with just one of the problems so i understand the process... what exactly is it asking?

Thank you

How would i continue that process for problems such as sin(x-pi)? I don't remember ever using triangles for these problems... only algebra... so i'm a bit confused