SOLUTION: could you please help me with this question? Determine the non-permissible values for the following expression: sin(x)+1/cos^2(x)-1

Algebra ->  Trigonometry-basics -> SOLUTION: could you please help me with this question? Determine the non-permissible values for the following expression: sin(x)+1/cos^2(x)-1       Log On


   

Question 1011910: could you please help me with this question?
Determine the non-permissible values for the following expression: sin(x)+1/cos^2(x)-1
Found 2 solutions by Boreal, macston:
Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
sin(x)+1/cos^2(x)-1,
cos^2 ( x)-1=sin^2x
it occurs whenever cos x=1 or sin^2 x=0
That occurs at 0 and pi on the interval (0,2pi)

Answer by macston(5194) About Me  (Show Source):
You can put this solution on YOUR website!
.
The non-permissible values would cause
division by zero (undefined), so:
.
cos%5E2%28x%29-1=0 is not permitted.
.
cos%5E2%28x%29-1=0
.
cos%5E2%28x%29=1
.
sqrt%28cos%5E2%28x%29%29=sqrt%281%29
.
cos%28x%29=+-%281%29
.
arccos%281%29=0 and arccos%28-1%29=180
.
ANSWER: Non-permissible values are x=0
degrees or x=180 degrees.