Question #139ce

1 Answer
Jan 6, 2018

The answer is:a=1.10714871+pina=1.10714871+πn

Explanation:

If you plug this into the calculator as arctan(2)arctan(2), you get the answer:
a=1.10714871+pina=1.10714871+πn
There are infinitely many values that make sense, since we can keep rotating the angle around piπ radians around the unit circle.

Now, let's do something to strengthen your understanding:
Remember that tantheta=sintheta/costhetatanθ=sinθcosθ which really represents: (Deltay)/(Deltax).
This question is asking us this:
"At what angle does the slope equal 2?"

If tana=2,
tana=(2sina)/cosa
Therefore, we are trying to solve a in the picture:
I made this
Now, using the Pythogorean theorem, we can find x.
1^2=x^2+(2x)^2
1=x^2+4x^2
1=5x^2
1/5=x^2
sqrt (1/5)=x

Therefore, the two legs are sqrt (1/5) and 2sqrt(1/5) which means that sqrt(1/5)=cosa and 2sqrt(1/5)=sina

It is interesting of how you can figure out so much with just an information.

You can use these information to double check whether you were right or not.