Solve for x if cos(2x+60)=-1
Mathematics · Middle School · Tue Nov 03 2020
Answered on
Given:
cos (2x + 60) = -1
Solve for x.
Solution:
Transpose 60 on the other side of the equation, note that when transposing a number the sign changes.
cos (2x + 60) = -1
cos (2x) = -1-60
cos (2x) = -59
Divide both sides by 2.
cos x = -59/2
cos x = -29.5
Transpose cosine on the other side, hence when tranposing a trigonometric function, it will become inverse, or arc.
x = cos^-1 (-29.5)
x = DNE
x DNE since the domain for cosine is only from 0 to 2pi, and -29.5 is more than the domain of the cosine.