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105 LearnersLast updated on December 11, 2025

Arcsin 2 is undefined in the real number system. The arcsine function, the inverse of the sine function, cannot return an angle for a sine value of 2, as the sine of any real angle is restricted to the range [-1, 1].
Arcsin 2 does not represent a real angle since the sine function only outputs values between -1 and 1. The arcsine function, being the inverse, is thus defined only for inputs within this range. Therefore, arcsin 2 is undefined in the context of real numbers.
The arcsin function is defined as arcsin: [-1, 1] → [-π/2, π/2], meaning its domain is limited to values between -1 and 1.
Since 2 is outside this range, arcsin 2 does not produce a valid angle in the real number system.
Although arcsin 2 is undefined in the real number system, it can be expressed using complex numbers.
In complex analysis, arcsin(z) is defined for any complex number z.
The calculation involves logarithms and imaginary numbers, but such expressions are beyond typical real number trigonometry.


Understanding the domain of arcsin is crucial. Here are some tips: -
Always remember that arcsin is only defined for inputs in the range [-1, 1].
For real number calculations, any input outside this range makes arcsin undefined.
Visualize the sine curve to confirm that it never exceeds 1 or drops below -1.
Misunderstanding the domain of arcsin can lead to errors.
Here’s how to avoid common pitfalls:
Determine if arcsin 2 is defined.
Undefined in the real number system.
Arcsin 2 requires the input to be within [-1, 1].
As 2 is outside this range, arcsin 2 does not yield a real angle.
What is the domain of the arcsin function?
The domain is [-1, 1].
The arcsin function is defined for inputs between -1 and 1, as these correspond to the range of the sine function output.
Can arcsin 2 be expressed using complex numbers?
Yes, using complex analysis.
In complex analysis, arcsin 2 can be expressed with complex numbers, though it requires advanced mathematics beyond basic trigonometry.
What is the sine function's range?
[-1, 1]
The sine function outputs values between -1 and 1, which limits the domain for its inverse, the arcsin function.
Why is arcsin 2 undefined in real numbers?
Because 2 is outside the range [-1, 1].
The sine function only produces values from -1 to 1.
Thus, arcsin cannot accept 2 as a valid input in real number calculations.
Jaskaran Singh Saluja is a math wizard with nearly three years of experience as a math teacher. His expertise is in algebra, so he can make algebra classes interesting by turning tricky equations into simple puzzles.
: He loves to play the quiz with kids through algebra to make kids love it.






