Arctangent is the inverse function of tangent. It is also written as arctan or tan-1. If y = tan x, then x = arctan y.
tan-1 1 = 450 or arctangent (1) = 450. This means that the angle 450 has tangent equal to 1.
].A. 
B. 
C. 
D. 
Correct Answer: B
Step 1: Let B = arctan
. Then tan B = .
Step 2: So, sec [arctan
] = sec [arctan(tan B)].
Step 3: = sec B
Step 4: From the figure, we observe that sec B =
.
Step 5: So, sec[arctan
] =
.
Q1: What is arctan(1)?
Q2: The range of arctangent function is?
Q: What is the domain of the arctangent function?
A: The domain of the arctangent function is all real numbers.
Q: What is the range of the arctangent function?
A: The range of the arctangent function is (-π/2, π/2) radians or (-90°, 90°).
Q: How do I find the arctangent of a number?
A: Use a calculator or trigonometric tables to find the angle whose tangent is the given number.