The tangent function repeats every π radians. For x=arctan(y), Your calculator will give you the principal value, which is located in the interval -π/2 ≤ y ≤ π/2. 2.28 is greater than π/2. Take arctan(-1.16) and add π to the result, and you will get 2.28.hi,
may i know how to get arch tanget for -1.16?
When in calculator, radian mode, i use tan inver -1.16, but i cant get 2.28