exact value of sin(5pi/6-2pi)?  TOPIC_SOLVED

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exact value of sin(5pi/6-2pi)?

Postby sully039 on Fri Aug 05, 2011 10:44 pm

I'm not sure if I'm suppossed to find the value of 5pi/6 (which is 1/2) and then subtract 2pi from it. Or is it sin(5pi/6)-sin(2pi)?

Also, can anyone tell me how to figure out the equation of this tangent? I think the answer is tan(x-pi/4)-1, but I'm not sure. Graph is in link below.
http://imageshack.us/photo/my-images/14/graphkh.jpg

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Re: exact value of sin(5pi/6-2pi)?  TOPIC_SOLVED

Postby maggiemagnet on Sat Aug 06, 2011 2:37 pm

sully039 wrote:I'm not sure if I'm suppossed to find the value of 5pi/6 (which is 1/2) and then subtract 2pi from it. Or is it sin(5pi/6)-sin(2pi)?

Wow! They were supposed to teach you about functions before diving so deep into trig! To get up to speed, try a lesson on functions and another on function notation. Specifically, you'll see that the parentheses in function notation is not the same as parentheses for multiplication! :shock: In this case, you have the function, sine, being taken of the simplified value of -pi/6.

sully039 wrote:Also, can anyone tell me how to figure out the equation of this tangent? I think the answer is tan(x-pi/4)-1, but I'm not sure. Graph is in link below.
http://imageshack.us/photo/my-images/14/graphkh.jpg

Since the graph is already flexed back downward (in other words, it's not in the middle of its flexing) at (0, -1), then the function isn't going to be tan(something) - 1. It looks to me like you have a phase shift going on, but that's about all.

In f(x) = tan(x), what is the value of tan(-pi/4)? How can you relate that to the graph?

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