Question

Can you solve and show me the work in these two equations?
cos(3x)=-1
tan (theta)=-1

Answer 1

Best way to solve it is using a calculator and taking advantage of the arc functions (cos^-1 or tan^-1) to solve it.

arcCos^-1 (-1)= answer
arcTan^-1 (-1) = answer

if you can't use a calculator, then try to remember the unit circle.

cos(y) = -1 when y = pi or 180 degrees
So work backwards. cos y = cos 3x = -1

y=3x

x= pi/3 or 60 degrees. Since you didn't include bounds in the equation, the solution set is actually (60+120*n) where n is any integer. So x=60, 180, 300, 420... all work.

Same goes for the tangent. Just work backwards.

Answer 2

F&arrowbold;