cos(0.5x)=2/√2 equation
The teacher will be very surprised to see your correct solution 😉
The solution
Detail solution
Given the equation
$$\cos{\left(\frac{x}{2} \right)} = \frac{2}{\sqrt{2}}$$
- this is the simplest trigonometric equation
As right part of the equation
modulo =
$$\sqrt{2} > 1$$
but cos
can no be more than 1 or less than -1
so the solution of the equation d'not exist.
Sum and product of roots
[src]
/ / ___\\ / / ___\\
4*pi - 2*I*im\acos\\/ 2 // + 2*I*im\acos\\/ 2 //
$$\left(4 \pi - 2 i \operatorname{im}{\left(\operatorname{acos}{\left(\sqrt{2} \right)}\right)}\right) + \left(2 i \operatorname{im}{\left(\operatorname{acos}{\left(\sqrt{2} \right)}\right)}\right)$$
$$4 \pi$$
/ / ___\\ / / ___\\
4*pi - 2*I*im\acos\\/ 2 // * 2*I*im\acos\\/ 2 //
$$\left(4 \pi - 2 i \operatorname{im}{\left(\operatorname{acos}{\left(\sqrt{2} \right)}\right)}\right) * \left(2 i \operatorname{im}{\left(\operatorname{acos}{\left(\sqrt{2} \right)}\right)}\right)$$
/ / / ___\\\ / / ___\\
4*\2*pi*I + im\acos\\/ 2 ///*im\acos\\/ 2 //
$$4 \left(\operatorname{im}{\left(\operatorname{acos}{\left(\sqrt{2} \right)}\right)} + 2 i \pi\right) \operatorname{im}{\left(\operatorname{acos}{\left(\sqrt{2} \right)}\right)}$$
/ / ___\\
x_1 = 4*pi - 2*I*im\acos\\/ 2 //
$$x_{1} = 4 \pi - 2 i \operatorname{im}{\left(\operatorname{acos}{\left(\sqrt{2} \right)}\right)}$$
/ / ___\\
x_2 = 2*I*im\acos\\/ 2 //
$$x_{2} = 2 i \operatorname{im}{\left(\operatorname{acos}{\left(\sqrt{2} \right)}\right)}$$
x1 = 12.5663706143592 - 1.76274717403909*i