"Amy" <tiffanyfassbender@[EMAIL PROTECTED]
> wrote in message
news:rk2md05pcgab58qe4ja7q550bdfl531at5@[EMAIL PROTECTED]
> I need to find all the trig. functions for an angle in statndard
> position having its terminal side defined by the equation y = - x.
In addition to what Lynn advised: When 'converting' equations of
nonvertical lines into angles in standard position, you may find useful
(at
times a least) to 'figure out the relevant angle' with the relation****p:
tan(angle) = slope
Determine the slope with usual means and plug it into the formula, giving
in
this case:
tan(angle) = -1
....and solve for the 'angle'. Geometrically, using right triangle
ratios,
you have a right triangle with opposite and adjacent sides both 1.
Remember
"-1" has an understood denominator of 1. Don't worry too much about
signs(+/-) at this point; just worry about the numbers, so at this point
you
have a right triangle with both legs of 1. Even if you don't already
recognize what kind of special triangle this is, or in cases where it's
NOT
a special triangle, you can always use Pythagoras to solve for the
remaining
side, thus allowing you to determine all six trig ratios of the angle.
For the signs(+/-) you said x>0, meaning the terminal side of the angle
lies
in Q4 such that 3pi/2<angle<2pi, so keep that in mind when determining the
signs(+/-) of the other trig functions, too.
Q1 all positive
Q2 sine and its reciprocal (cosecant) are positive
Q3 tangent and its reciprocal (cotangent) are positive
Q4 cosine and its reciprocal (secant) are positive
--
Darrell
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