# SOLUTION: I need help solving this equation: 4cos^2theta+4sintheta=5

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 Click here to see ALL problems on Trigonometry-basics Question 556880: I need help solving this equation: 4cos^2theta+4sintheta=5Answer by htmentor(789)   (Show Source): You can put this solution on YOUR website!4cos^2theta+4sintheta=5 ======================= For simplicity, let theta = x If we use the identity, cos^2(x) = 1 - sin^2(x), we have a polynomial in sin(x): 4(1 - sin^2(x)) + 4sin(x) = 5 Divide through by 4, and simplifiy: sin^2(x) - sin(x) + 1/4 = 0 This can be factored as: (sin(x)-1/2)(sin(x)-1/2) = 0 So we need to find solutions of sin(x) = 1/2 In the first quadrant, this is x = 30 deg (pi/6)