# Geometry and Sin

Topics: Geometry, Maxima and minima, Fermat's theorem Pages: 2 (331 words) Published: June 1, 2013
1 (a)Show that = tan θ.
(b)Hence find the value of cot in the form a + , where a, b .
2 If x satisfies the equation , show that 11 tan x = a + b, where a, b +.

3 The graph below shows y = a cos (bx) + c.

Find the value of a, the value of b and the value of c.

4 The diagram below shows two concentric circles with centre O and radii 2 cm and 4 cm. The points P and Q lie on the larger circle and angle POQ = x, where 0 < x < π2.

Show that the area of the shaded region is 8 sin x – 2x.

6 In the diagram below, AD is perpendicular to BC.
CD = 4, BD = 2 and AD = 3. =  and = .

Find the exact value of cos ( − ).

8 Let sin x = s.
(a)Show that the equation 4 cos 2x + 3 sin x cosec3 x + 6 = 0 can be expressed as 8s4 – 10s2 + 3 = 0.
(b)Hence solve the equation for x, in the interval [0, π].

9 A particle P moves in a straight line with displacement relative to origin given by
s = 2 sin (πt) + sin(2πt), t ≥ 0,
where t is the time in seconds and the displacement is measured in centimetres. (i) Write down the period of the function s.

10 The diagram below shows a curve with equation y = 1 + k sin x, defined for 0 ≤ x ≤ 3π.
The point A lies on the curve and B(a, b) is the maximum point.
(a)Show that k = –6.
(b)Hence, find the values of a and b.

11 The depth, h (t) metres, of water at the entrance to a harbour at t hours after midnight on a particular day is given by
h (t) = 8 + 4 sin...

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