The coordinates of C are 4,6 because thats the rule for y=x
You have to know that the graph of the arctangent function is a flat S-shaped curve that goes through (0, 0) and has asymptotes at ±π/2. The factor of 2 that multiplies it here expands it vertically so the asymptotes are at ±π. The +3 added to the x causes it to be shifted to the left by 3 units.
Given:
The equation is

To find:
The value of b.
Solution:
We have,

Subtracting both sides by
, we get




Therefore, the value of b is
.