Sunday, June 14, 2015

Solve 2cos^2(x) + 3sin(x) - 3 = 0 for x in the range [0 , 2pi]

We have to solve 2*(cos x)^2 + 3*sin x - 3 = 0 for x in
[0, 2*pi]


2*(cos x)^2 + 3*sin x - 3 =
0


use (cos x)^2 = 1 - (sin
x)^2


=> 2 - 2*(sin x)^2 + 3sin x - 3 =
0


=> 2*(sin x)^2 - 3*sin x + 1 =
0


=> 2*(sin x)^2 - 2*sin x - sin x + 1 =
0


=> 2*sin x( sin x - 1) -1 (sin x - 1) =
0


=>(2*sin x - 1)(sin x - 1) =
0


2*sin x - 1 = 0


=>
sin x = 1/2


=> x = arc sin (1/2) = pi/6 and
5*pi/6


sin x - 1 = 0


=>
sin x = 1


=> x = arc sin
(1)


=> x =
pi/2


The required values of x are x = pi/2, x
= pi/6 and x = 5*pi/6

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