SOLUTION: How can you use an identity to find cos(x) and tan(x) if cot(x) = -2 and cos(x) < 0?

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Question 1063064: How can you use an identity to find cos(x) and tan(x) if cot(x) = -2 and cos(x) < 0?
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
tan%28x%29=-1%2F2
tan%5E2%28x%29%2B1=sec%5E2%28x%29
sec%5E2%28x%29=1%2F4%2B1
sec%5E2%28x%29=5%2F4
1%2Fcos%5E2%28x%29=5%2F4
cos%5E2%28x%29=4%2F5
cos%28x%29=0+%2B-+2%2Fsqrt%285%29
Since we know cos%28x%29%3C0,
cos%28x%29=-%282%2F5%29sqrt%285%29