Solving Trig Equations (1 Viewer)

Lemiixem · Mar 6, 2012

Solve for 0 < x < 2Pie

Cos 2x = Cos x

Tan^2 x - 1 = 0

Solve for -Pie < x < Pie

Cos^2 x - Sinx = -1

Sin^3 x - Sinx = 0

nightweaver066 · Mar 6, 2012

$1. cos2x = cosx$

$2cos^2x - 1 = cosx$

$2cos^2x - cosx - 1 = 0$

$Apply quadratic formula or factorise to get solutions$

$2. tan^2x - 1 = 0$

$tan^2x = 1$

$tanx = \pm 1$

$tanx = 1 $ or $ tanx = -1$

$Solve both for solutions$

$3. cos^2x - sinx = -1$

$(1 - sin^2x) - sinx = -1$

$sin^2x + sinx - 2 = 0$

$(sinx + 2)(sinx - 1)= 0$

$Solve this for the solutions$

$4. sin^3x - sinx = 0$

$sinx(sin^2x - 1) =0$

$sinx(sinx + 1)(sinx-1) = 0$

$Solve from here$

Solving Trig Equations (1 Viewer)

Lemiixem

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nightweaver066

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