Solve the equation
\( \tan(x + 45^\circ) = 2 \cot x \quad \text{for } 0^\circ < x < 180^\circ. \)
Solution
Use the tangent addition formula:
\(
\tan(x+45^\circ)=\frac{\tan x+1}{\,1-\tan x\,}.
\)
Also \(\cot x=\dfrac{1}{\tan x}\).
Let \(t=\tan x\). Then
\[
\frac{t+1}{1-t}=2\cdot\frac{1}{t}
\;\Rightarrow\; t(t+1)=2(1-t)
\]
\[
\Rightarrow\; t^2+t=2-2t
\;\Rightarrow\; t^2+3t-2=0.
\]
Solve the quadratic:
\[
t=\frac{-3\pm\sqrt{9+8}}{2}
=\frac{-3\pm\sqrt{17}}{2}
\approx 0.5616\;\text{ or }\;-3.5616.
\]
\[
\tan x\approx0.5616 \Rightarrow x\approx \arctan(0.5616)=29.3^\circ,
\]
\[
\tan x\approx-3.5616 \Rightarrow x\text{ in QII } =180^\circ-\arctan(3.5616)=105.7^\circ.
\]
Final answer
\(\boxed{x\approx29.3^\circ,\;105.7^\circ}\)
Log in to record attempts.