How do you solve the equation 0º ≤ x < 360º 2 cos² x + 3 cos x - 2 = 0 ?

1 Answer
Cem Sentin
Feb 22, 2018

#x_1=60º# and #x_2=300º#

Explanation:

#2(cosx)^2+3cosx-2=0#

#(cosx+2)*(2cosx-1)=0#

From first multiplier, no solution due to #-1<=cosx<=1# condition.

From first multiplier, #cosx=1/2#

Thus, #x_1=60º# and #x_2=300º#

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