# Trig Function Help: Get Answers Now

• Eric Manuel
In summary, the conversation involved finding the value of cos2t using the double angle formula. The problem provided a value for cot and asked to find the corresponding value for tan. The conversation also discussed using a calculator and finding the reference triangle to solve the problem. A helpful link was also provided for further understanding.

#### Eric Manuel

thanks

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Can you give the entire problem?

Jimmy Johnson said:
Can you give the entire problem?

all that's given is that

What is the question? What are you asked to find?

MostlyHarmless said:
What is the question? What are you asked to find?
what is =cos2x

What is x supposed to be? Is the given problem in terms of t? Are you trying to solve for t and then plug that value in for x?

its basically asking you to use the double angle formula
but I am not sure how to find those values

If you're simply trying to find t, then use cot = 1/tan... If you have a value for t why do you need to use the double angle identities?

to find what cos2t is ...

you can find what tan is from cot
then i drew a triangle and got the hypot to be sqrt(41)

but how do i do that math

formula for cos2t = cos^2(t) - sin^2(t)

Are you forbidden from using a calculator?

Jimmy Johnson said:
Are you forbidden from using a calculator?

teacher said u can use it
but need to know how to do it without one for test

Well that may have been useful information at the start...

you have cot = -5/4, find what tan is then recall tan = sin/cos ... or recall cot = cos/sin...

well i worked it out and i believe i got the answer to be 9/41

That's what I'm getting