Re: [Math4u] trig stuff

To get the answer for cos(3pi/5), you must have your calculator in
radian mode.

For arccsc(-2.56) in degrees, you must have your calculator in degree
mode.

If arccsc(-2.56) = x, then csc(x)=-2.56, 1/sin(x)=-2.56, sin(x)=-1/2.56
so x=arcsin(-1/2.56)

The calculator gives an answer of -22.99, so the proper answers in
0<=x<=360 are 360-22.99 and 180+22.99. Look at the unit circle to see
why this is correct.

-- Rick

--- Tim Johnson <skinny@kwic.com> wrote:

> Can someone explain to me how this works out cos(3pi/5) the answer in
> the
> book is -309017
>
>
>
> Also csc-1(-2.56) answers 202.99,337.01
>
>

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