tmua 2020 Q18

tmua · Uk · paper1 1 marks Quadratic trigonometric equations
Find the number of solutions and the sum of the solutions of the equation
$$1 - 2\cos^2 x = |\cos x|$$
where $0 \leq x \leq 180^{\circ}$
A Number of solutions $= 2$ Sum of solutions $= 180^{\circ}$
B Number of solutions $= 2$ Sum of solutions $= 240^{\circ}$
C Number of solutions $= 3$ Sum of solutions $= 180^{\circ}$
D Number of solutions $= 3$ Sum of solutions $= 360^{\circ}$
E Number of solutions $= 4$ Sum of solutions $= 240^{\circ}$
F Number of solutions $= 4$ Sum of solutions $= 360^{\circ}$
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Find the number of solutions and the sum of the solutions of the equation

$$1 - 2\cos^2 x = |\cos x|$$

where $0 \leq x \leq 180^{\circ}$

A Number of solutions $= 2$ Sum of solutions $= 180^{\circ}$

B Number of solutions $= 2$ Sum of solutions $= 240^{\circ}$

C Number of solutions $= 3$ Sum of solutions $= 180^{\circ}$

D Number of solutions $= 3$ Sum of solutions $= 360^{\circ}$

E Number of solutions $= 4$ Sum of solutions $= 240^{\circ}$

F Number of solutions $= 4$ Sum of solutions $= 360^{\circ}$