Angles are in radians; use the stated domain. Given y=cos(x) + 2 tan(x), cos(x) 0, find dydx. Hence

Question

Angles are in radians; use the stated domain. Given y=cos(x) + 2 tan(x), cos(x) 0, find dydx. Hence find its value at x= pi4. Show that the gradient is positive everywhere the function is defined.

Accepted Answer

$\dfrac{\mathrm{d}y}{\mathrm{d}x}=2\sec^2x-\sin x$; at $x=\dfrac\pi4$, $4-\dfrac{\sqrt2}{2}$. The gradient is positive throughout its domain.

Tangent derivatives

Tangent derivatives

Solution:

Solution locked