Question Number 97988 by abdomathmax last updated on 10/Jun/20
$$\mathrm{calculate}\:\mathrm{by}\:\mathrm{recurrence}\:\mathrm{A}_{\mathrm{n}} =\int_{\mathrm{0}} ^{\frac{\pi}{\mathrm{4}}} \:\frac{\mathrm{dx}}{\mathrm{cos}^{\mathrm{n}} \mathrm{x}} \\ $$