1.

The number of solution(s) of the trigonometric equation sec^2x+cosec^2x-sin2x-3=0, in [0, 4pi], is

Answer»

2
4
6
8

Solution :`sec^2x + cosec^2x = sin2x +3`
`1+tan^2x+1 + cot^2x=1+sin2x+2`
`2+tan^2x+cot^2x =(sin x+cosx)^2 +2`
Range of LHS is `[4,oo]`
Range of RHS is [2,4]
So SOLUTIONWILL exist when
sin2x=1 and tanx=cotx= `pm`1
`2x=x/2(4n+1)`
`x=pi/4,(5pi)/4,(9pi)/4,(13pi)/4` at these x the VALUE of tan x = cot x =1
so number of solution = 4


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