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The blades of a wind turbine have a diameter of 16m and rotate clockwise at a constant speed, 1 revolution every 4 seconds. The blades are fixed on a shaft such that the tips of the blades are always at least 7m above the ground. The point Q lies at the tip of one of the blades.
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Let h be the height, in meters, of Q above the ground. After t minutes, h is given by h(t)=acos(bt)+c, where a,b,c∈R and a>0.
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Show that Q starts at the highest possible point.
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Find the values of a, b and c.
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A spherical white blood cell appears as a circle with circumference 6π×10−5m.
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Write down the radius of the cell.
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Find the volume of the cell, giving your answer in the form π(a×10k)m3, where a<10 and k∈Z.
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Find all the solutions to the equation sin2θ=√3cosθ, where 0≤θ≤2π.
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The points P and Q lie on a circle with center O and radius r such that PO^Q=2 radians.
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The perimeter of the shaded region is 7π.
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Find the value of r.
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Hence find the area of the region inside the circle that is not shaded.
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A chocolate ball is formed from a spherical shell with diameter d and thickness 2mm. The shell is filled on the inside with 3cm3 of caramel.
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Show that d=2.19cm.
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Hence find the volume of the chocolate shell.
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The diagram below shows triangle ABC
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- [4]
Find the value of x.
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Hence or otherwise, find the value of the angle θ to the nearest degree.