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Grade 11Trigonometry

sir i didnt got this question which u taught in video i got {solve for x:sin2x-4cosx=1}

Profile image of arti
9 Years agoGrade 11
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2 Answers

Profile image of Akshay
9 Years ago
sin2x-4cosx=12sinxcosx - 4cosx = 12cosx(sinx - 2) = 12cosx = 1Cosx =1/2Cosx = cos60°x= π/3 or 60°Sinx - 2 = 1sinx = 3sinx can`t be equal to 3 as sinx lies between [-1,1].
Profile image of Akshay
9 Years ago
sin2x-4cosx=1 ; 2sinxcosx - 4cosx = 1 ; 2cosx(sinx - 2) = 1 ; 2cosx = 1 ; Cosx =1/2 ; Cosx = cos60° ; x= π/3 or 60° ; sinx - 2 = 1 ; sinx = 3 ; sinx can`t be equal to 3 as sinx lies between [-1,1].