Mister Exam

tgx+ctgx=3/2 equation

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Numerical solution:

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The solution

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tan(x) + cot(x) = 3/2
$$\tan{\left(x \right)} + \cot{\left(x \right)} = \frac{3}{2}$$
Detail solution
Given the equation
$$\tan{\left(x \right)} + \cot{\left(x \right)} = \frac{3}{2}$$
transform
$$\tan{\left(x \right)} + \cot{\left(x \right)} - \frac{5}{2} = 0$$
$$\tan{\left(x \right)} + \cot{\left(x \right)} - \frac{5}{2} = 0$$
Do replacement
$$w = \cot{\left(x \right)}$$
Given the equation:
$$w + \tan{\left(x \right)} - \frac{5}{2} = 0$$
transform:
$$w + \tan{\left(x \right)} - \frac{5}{2} = 0$$
Expand brackets in the left part
-5/2 + w + tanx = 0

Move free summands (without w)
from left part to right part, we given:
$$w + \tan{\left(x \right)} = \frac{5}{2}$$
Divide both parts of the equation by (w + tan(x))/w
w = 5/2 / ((w + tan(x))/w)

We get the answer: w = 5/2 - tan(x)
do backward replacement
$$\cot{\left(x \right)} = w$$
substitute w:
The graph
Rapid solution [src]
         /    /        ___\\     /    /        ___\\
         |    |3   I*\/ 7 ||     |    |3   I*\/ 7 ||
x1 = I*im|atan|- - -------|| + re|atan|- - -------||
         \    \4      4   //     \    \4      4   //
$$x_{1} = \operatorname{re}{\left(\operatorname{atan}{\left(\frac{3}{4} - \frac{\sqrt{7} i}{4} \right)}\right)} + i \operatorname{im}{\left(\operatorname{atan}{\left(\frac{3}{4} - \frac{\sqrt{7} i}{4} \right)}\right)}$$
         /    /        ___\\     /    /        ___\\
         |    |3   I*\/ 7 ||     |    |3   I*\/ 7 ||
x2 = I*im|atan|- + -------|| + re|atan|- + -------||
         \    \4      4   //     \    \4      4   //
$$x_{2} = \operatorname{re}{\left(\operatorname{atan}{\left(\frac{3}{4} + \frac{\sqrt{7} i}{4} \right)}\right)} + i \operatorname{im}{\left(\operatorname{atan}{\left(\frac{3}{4} + \frac{\sqrt{7} i}{4} \right)}\right)}$$
x2 = re(atan(3/4 + sqrt(7)*i/4)) + i*im(atan(3/4 + sqrt(7)*i/4))
Sum and product of roots [src]
sum
    /    /        ___\\     /    /        ___\\       /    /        ___\\     /    /        ___\\
    |    |3   I*\/ 7 ||     |    |3   I*\/ 7 ||       |    |3   I*\/ 7 ||     |    |3   I*\/ 7 ||
I*im|atan|- - -------|| + re|atan|- - -------|| + I*im|atan|- + -------|| + re|atan|- + -------||
    \    \4      4   //     \    \4      4   //       \    \4      4   //     \    \4      4   //
$$\left(\operatorname{re}{\left(\operatorname{atan}{\left(\frac{3}{4} - \frac{\sqrt{7} i}{4} \right)}\right)} + i \operatorname{im}{\left(\operatorname{atan}{\left(\frac{3}{4} - \frac{\sqrt{7} i}{4} \right)}\right)}\right) + \left(\operatorname{re}{\left(\operatorname{atan}{\left(\frac{3}{4} + \frac{\sqrt{7} i}{4} \right)}\right)} + i \operatorname{im}{\left(\operatorname{atan}{\left(\frac{3}{4} + \frac{\sqrt{7} i}{4} \right)}\right)}\right)$$
=
    /    /        ___\\       /    /        ___\\     /    /        ___\\     /    /        ___\\
    |    |3   I*\/ 7 ||       |    |3   I*\/ 7 ||     |    |3   I*\/ 7 ||     |    |3   I*\/ 7 ||
I*im|atan|- - -------|| + I*im|atan|- + -------|| + re|atan|- - -------|| + re|atan|- + -------||
    \    \4      4   //       \    \4      4   //     \    \4      4   //     \    \4      4   //
$$\operatorname{re}{\left(\operatorname{atan}{\left(\frac{3}{4} - \frac{\sqrt{7} i}{4} \right)}\right)} + \operatorname{re}{\left(\operatorname{atan}{\left(\frac{3}{4} + \frac{\sqrt{7} i}{4} \right)}\right)} + i \operatorname{im}{\left(\operatorname{atan}{\left(\frac{3}{4} - \frac{\sqrt{7} i}{4} \right)}\right)} + i \operatorname{im}{\left(\operatorname{atan}{\left(\frac{3}{4} + \frac{\sqrt{7} i}{4} \right)}\right)}$$
product
/    /    /        ___\\     /    /        ___\\\ /    /    /        ___\\     /    /        ___\\\
|    |    |3   I*\/ 7 ||     |    |3   I*\/ 7 ||| |    |    |3   I*\/ 7 ||     |    |3   I*\/ 7 |||
|I*im|atan|- - -------|| + re|atan|- - -------|||*|I*im|atan|- + -------|| + re|atan|- + -------|||
\    \    \4      4   //     \    \4      4   /// \    \    \4      4   //     \    \4      4   ///
$$\left(\operatorname{re}{\left(\operatorname{atan}{\left(\frac{3}{4} - \frac{\sqrt{7} i}{4} \right)}\right)} + i \operatorname{im}{\left(\operatorname{atan}{\left(\frac{3}{4} - \frac{\sqrt{7} i}{4} \right)}\right)}\right) \left(\operatorname{re}{\left(\operatorname{atan}{\left(\frac{3}{4} + \frac{\sqrt{7} i}{4} \right)}\right)} + i \operatorname{im}{\left(\operatorname{atan}{\left(\frac{3}{4} + \frac{\sqrt{7} i}{4} \right)}\right)}\right)$$
=
/    /    /        ___\\     /    /        ___\\\ /    /    /        ___\\     /    /        ___\\\
|    |    |3   I*\/ 7 ||     |    |3   I*\/ 7 ||| |    |    |3   I*\/ 7 ||     |    |3   I*\/ 7 |||
|I*im|atan|- - -------|| + re|atan|- - -------|||*|I*im|atan|- + -------|| + re|atan|- + -------|||
\    \    \4      4   //     \    \4      4   /// \    \    \4      4   //     \    \4      4   ///
$$\left(\operatorname{re}{\left(\operatorname{atan}{\left(\frac{3}{4} - \frac{\sqrt{7} i}{4} \right)}\right)} + i \operatorname{im}{\left(\operatorname{atan}{\left(\frac{3}{4} - \frac{\sqrt{7} i}{4} \right)}\right)}\right) \left(\operatorname{re}{\left(\operatorname{atan}{\left(\frac{3}{4} + \frac{\sqrt{7} i}{4} \right)}\right)} + i \operatorname{im}{\left(\operatorname{atan}{\left(\frac{3}{4} + \frac{\sqrt{7} i}{4} \right)}\right)}\right)$$
(i*im(atan(3/4 - i*sqrt(7)/4)) + re(atan(3/4 - i*sqrt(7)/4)))*(i*im(atan(3/4 + i*sqrt(7)/4)) + re(atan(3/4 + i*sqrt(7)/4)))
Numerical answer [src]
x1 = 0.785398163397448 - 0.397682730611953*i
x2 = 0.785398163397448 + 0.397682730611953*i
x2 = 0.785398163397448 + 0.397682730611953*i