Inverse Trigonometric Functions (HL only)

Inverse Trigonometric Functions (HL only)

TGM Original

\(\sec x=\dfrac1{\cos x},\quad\mathrm{cosec}\,x=\dfrac1{\sin x},\quad\cot x=\dfrac{\cos x}{\sin x}\), each with a nonzero denominator.

The inverse trigonometric functions return a single principal angle. They are different from reciprocal ratios.

FunctionDomainRange
\(\arcsin x\)\([-1,1]\)\(\left[-\dfrac\pi2,\dfrac\pi2\right]\)
\(\arccos x\)\([-1,1]\)\([0,\pi]\)
\(\arctan x\)\(\mathbb R\)\(\left(-\dfrac\pi2,\dfrac\pi2\right)\)

For example, \(\arcsin(\sin\dfrac{5\pi}{6})=\dfrac\pi6\), because the returned value must lie in the principal range. The graphs arise by reflecting appropriately restricted sine, cosine and tangent graphs in \(y=x\).

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