cos(x)=pi/2 equation
The teacher will be very surprised to see your correct solution 😉
The solution
Detail solution
Given the equation
$$\cos{\left(x \right)} = \frac{\pi}{2}$$
- this is the simplest trigonometric equation
As right part of the equation
modulo =
True
but cos
can no be more than 1 or less than -1
so the solution of the equation d'not exist.
/ /pi\\
x1 = 2*pi - I*im|acos|--||
\ \2 //
$$x_{1} = 2 \pi - i \operatorname{im}{\left(\operatorname{acos}{\left(\frac{\pi}{2} \right)}\right)}$$
/ /pi\\ / /pi\\
x2 = I*im|acos|--|| + re|acos|--||
\ \2 // \ \2 //
$$x_{2} = \operatorname{re}{\left(\operatorname{acos}{\left(\frac{\pi}{2} \right)}\right)} + i \operatorname{im}{\left(\operatorname{acos}{\left(\frac{\pi}{2} \right)}\right)}$$
x2 = re(acos(pi/2)) + i*im(acos(pi/2))
Sum and product of roots
[src]
/ /pi\\ / /pi\\ / /pi\\
2*pi - I*im|acos|--|| + I*im|acos|--|| + re|acos|--||
\ \2 // \ \2 // \ \2 //
$$\left(2 \pi - i \operatorname{im}{\left(\operatorname{acos}{\left(\frac{\pi}{2} \right)}\right)}\right) + \left(\operatorname{re}{\left(\operatorname{acos}{\left(\frac{\pi}{2} \right)}\right)} + i \operatorname{im}{\left(\operatorname{acos}{\left(\frac{\pi}{2} \right)}\right)}\right)$$
/ /pi\\
2*pi + re|acos|--||
\ \2 //
$$\operatorname{re}{\left(\operatorname{acos}{\left(\frac{\pi}{2} \right)}\right)} + 2 \pi$$
/ / /pi\\\ / / /pi\\ / /pi\\\
|2*pi - I*im|acos|--|||*|I*im|acos|--|| + re|acos|--|||
\ \ \2 /// \ \ \2 // \ \2 ///
$$\left(2 \pi - i \operatorname{im}{\left(\operatorname{acos}{\left(\frac{\pi}{2} \right)}\right)}\right) \left(\operatorname{re}{\left(\operatorname{acos}{\left(\frac{\pi}{2} \right)}\right)} + i \operatorname{im}{\left(\operatorname{acos}{\left(\frac{\pi}{2} \right)}\right)}\right)$$
/ / /pi\\\ / / /pi\\ / /pi\\\
|2*pi - I*im|acos|--|||*|I*im|acos|--|| + re|acos|--|||
\ \ \2 /// \ \ \2 // \ \2 ///
$$\left(2 \pi - i \operatorname{im}{\left(\operatorname{acos}{\left(\frac{\pi}{2} \right)}\right)}\right) \left(\operatorname{re}{\left(\operatorname{acos}{\left(\frac{\pi}{2} \right)}\right)} + i \operatorname{im}{\left(\operatorname{acos}{\left(\frac{\pi}{2} \right)}\right)}\right)$$
(2*pi - i*im(acos(pi/2)))*(i*im(acos(pi/2)) + re(acos(pi/2)))
x1 = 6.28318530717959 - 1.02322747854755*i