Level:
Project ID:
2010014905
Source Problem:
Accepted:
0
Clonable:
1
Easy:
1
Identify the optimal first step convenient to solve the following trigonometric
equation. Do not consider the step which is possible but does not help to solve the
equation.
\[
\mathop{\mathrm{tg}}^2\nolimits x - 2\mathop{\mathrm{tg}}\nolimits x -3=0
\]
substitution \( \mathop{\mathrm{tg}}\nolimits x =y\)
\(\mathop{\mathrm{tg}}\nolimits x (\mathop{\mathrm{tg}}\nolimits x -2)=3\)
\(\frac{\sin^2 x}{\cos^2 x}-2\frac{\sin x}{\cos x}-3=0\)
\(\mathop{\mathrm{tg}}\nolimits x-2=3-\mathop{\mathrm{tg}}\nolimits x \)