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7sinx=6 qurstion?
can someone check if my working is correct?
7sinx=6
sinx=6/7
x=sin^-1(6/7)
x= 58.997
5 Answers
- TomVLv 74 months agoFavorite Answer
Remember the Unit Circle? "the angle whose (trig function) = x" usually has two answers in the interval [0, 2π). You have provided one of those answers. Let's look for the other one:
Recall: sin(π-x) = sin(π)cos(x) - cos(π)sin(x) = sin(x)
For every angle, x ≠ kπ/2 where k is an odd integer, there is another angle, π-x, that has the same sine value.
Arcsin(x) is a function that returns values in the first or fourth quadrant only, it is up to you to find the second solution in the second or third quadrant.
You found arcsin(6/7) = 58.997, but sin(360°-58.997) is also equal to 6/7.
The two values of x in the interval 0 ≤ x < 360 where 7sin(x) = 6 in the interval 0 ≤ x < 360° is:
x₁ = 58.997°
x₂ = 180 - 58.997 = 121.003°
There are an infinite number of angles coterminal with those two angles which also share the value of sine..
[Use your calculator to verify that sin(58.997°) and sin(121.003°) are both equal to 6/7 within roundoff error. On my calculator they are the same within 2 x 10^-39, a very small difference indeed. The difference is due solely to using a finite decimal string for the angles. The more significant digits used for the angle measure, the smaller that difference will be.]
- ?Lv 74 months ago
7 sin x = 6
sin x = 6/7
x = sin^-1(6/7)
x = 58.997
You are correct
line
x-intercept | sin^(-1)(6/7) ≈ 1.0297
x = 59° (degrees)
- rotchmLv 74 months ago
Almost all correct. Just recall that
sinx = 6/7 has two primary answers (and infinitely many answers).
You gave one of the primary answers.
The sin^-1 only gives you one. It is up to you to remember to find the other(s).
So, whats the other possible result? [think of your trig circle].
- llafferLv 74 months ago
Other than labeling your answer with degrees (so it's not confused with radians, which then would not be the correct answer), this is correct.