Question 28417: find the angle requested for the following
sin A= .2356(nearest degree) tan A= -2.4567 (nearest sec)
for the sin A i really have no idea what to do but for tan A= -2.4567 do i basically type it into the calc. like this tan (-2.4567)/3600
ok thats probably not right.
thank you very much for helping me out :) you don't understand how much this stuff just goes right over my head because the teacher likes to rush to get all the material covered. Thank you again
Answer by longjonsilver(2297)   (Show Source):
You can put this solution on YOUR website! Well first, sin, cos and tan are cyclical functions...they repeat themselves, so there are in fact an infinite number of answers for answer question. What the question usually tells you is a range of angles to quote from.
Anyway, you haven't, so you might as well quote the one answer that your calculator will store.
sinA = 0.2356
so there is an angle of a right angled triangle such that when you divide the opposite length by the hypotenuse length, that ratio is 0.2356.
Method:
well, we have an equation. And one fundamental rule of equations is "to remove something, you do the opposite".
We have sinA and we want the angle A by itself. So we need to remove the "sin" bit. So, the opposite of sin, as shown on your calculator is sin^(-1).
so A = sin^(-1)(0.2356).
A = 13.627 degrees
--> A = 14 degrees.
Physically, the opposite of sin being "sin^(-1)" doesn't make sense...it is just the way we write "opposite of sin", that is all.
Second one:
tanA = -2.4567
A = tan^(-1)(-2.4567)
A = -67.851 degrees.
Your calculator will convert this to degrees-minutes-seconds, using relevant button: ask your teacher to tell you which it is.
A = -67.851 degrees becomes
A = -67degrees 51minutes and 4seconds
Doing it from "first principles" is as follows:
.851 of 60minutes is 0.851*60 --> 51.06 minutes....so 51minutes
and
0.06 of 60 seconds is 0.06*60 --> 3.6 which is 4 seconds to the nearest second.
jon.
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