Answer
a) $1$
b) $0$
Work Step by Step
a) We know that:
$$sech(x)=\frac{2}{e^{x}+e^{-x}}$$
Substitute $x=0$ into the equation:
$$sech(0)=\frac{2}{e^{0}+e^{0}}=1$$
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b) We know that:
$$\cosh^{-1}(x)=\ln(x+\sqrt{x^{2}-1})$$
Substitute $x=1$ into the equation:
$$\cosh^{-1}(1)=\ln(1+\sqrt{1^{2}-1})=0$$
