# Thread: Trigonemetry Graphs

1. ## Trigonemetry Graphs

I got a Sin and Tan Graph.

The sin graph's formula: y = a sin x
The tan graph's formula: y = tan 1/a x

These two graphs cross at 120 degrees.

So that means:
a sin 120 = tan 1/a 120

But how can i find the value of a? Somewhere im missing something.

2. Originally Posted by janvdl
I got a Sin and Tan Graph.

The sin graph's formula: y = a sin x
The tan graph's formula: y = tan 1/a x

These two graphs cross at 120 degrees.

So that means:
a sin 120 = tan 1/a 120

But how can i find the value of a? Somewhere im missing something.
a=+/-2

How did I find these solutions - educated guess and check

OK really - use a numerical method which suggested that 2 might be a root,
checking proved that this was indeed the case, then symettry suggest -2
is also a root. Then there is some very nasty behaviour for small a which
I will have to think about.

RonL

3. Originally Posted by CaptainBlack
a=+/-2 +n*pi for n=0, +/-1, ...

RonL
Sorry, i saw only now you said you guessed.

So theres no way of calculating this???

4. Why is "a" so very nasty? I mean, for goodness' sake i'm only in matric, not varsity.

5. Off topic sorry.

Is matric/varsity a High School/College/Uni ?

6. Matric is the highest grade of high school.
Varsity means university.

7. Originally Posted by janvdl
Why is "a" so very nasty? I mean, for goodness' sake i'm only in matric, not varsity.
If you have something suitable try plotting

y=x sin(120) - tan(120/x)

for x=0.00001 to 1.

RonL