Answer:
Step-by-step explanation:
[tex]y=\sqrt{cos x+\sqrt{cos x+\sqrt{cos x+...\infty} } } \\or\\y=\sqrt{cos x+y} \\squaring\\y^{2} =cos x+y\\Differentiate~with~respect~to~x\\2y\frac{dy}{dx} =-sin~x+\frac{dy}{dx} \\(2y-1)\frac{dy}{dx} +sin~x=0[/tex]
