NTA Abhyas JEE Main2020MathematicsTrigonometric EquationsPractice
The number of solutions of the equation cot ⁡ x = cot ⁡ x + cosec x in 0,10 π is/are
Correct answer
5
Step-by-step solution
If x lies in 1 s t or 3 r d quadrant then cot x = cot x , thus equation becomes cot x = cot x + 1 sin x ⇒ 1 sin x = 0 , not possible If x lies in 2 n d or 4 t h quadrant, then cot x = - cot x , thus equation becomes - cot x = cot x + 1 sin x ⇒ - 2 cot x = 1 sin x ⇒ - 2 cos x sin x = sin x ⇒ sin x 1 + 2 cos x = 0 ⇒ cos x = - 1 2 ∵ sin x ≠ 0 ⇒ x = 2 π 3 is the only solution (In 2 n d quad.) In 0,2 π there is only one solution In 0,10 π , we get, five solutions