How do I solve #4 sin x + 9 cos x = 0# for #0 < x < 360# ?

1 Answer
Konstantinos Michailidis
Sep 25, 2015

Refer to explanation

Explanation:

We have that
#4 sinx + 9 cosx = 0=> 4 sinx = −9 cosx => sinx/cosx = −9/4 => tanx = −9/4 #

#x = tan^(-1)(−9/4) + pi*k#, for all integers #k#

For #0° < x < 360°#
#x = tan^(-1)(−9/4) + 180 ≈ 113.96°#
#x = tan^(-1)(−9/4) + 360 ≈ 293.96°#

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