I had 1/2 for a and pi/4 for b. I am a bit struggling with these newly added Transformations for AS mathematics. I know the graph of tan x, but from there I don't know what transformations do i apply to get to that graph.
Then you could use the tan(pi/4)=1 to get the vertical scaling a.
Agree with b=pi/4. What do you think for c at x=pi/4 so tan(pi/4-pi/4) = tan(0) = ... Write down the points and the equations clearly if necessary.