How do you solve $cosx*cotx=cosx$ ?

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Answer 1 · 2015-05-13T00:36:25

f(x) = cos x.cot x - cos x = 0
$f(x) = cos x.( cot x - 1) = 0$

Use the trig unit circle as proof:

a. $cos x = 0 --> x = pi/2 and x = (3pi)/2$

b. $cot x = 1 -> x = pi/4 and x = (5pi)/4$

Within the period $(0, 2pi)$ , there are 4 answers: $pi/4; pi/2; (5pi)/4; and (3pi)/2$

How do you solve cosx*cotx=cosxcosx*cotx=cosx?