Sine function in equation issue

In summary: Consider a triangle ABC. Angle at C is a right angle, so AB is the hypotenuse. Consider angle at A. The sine of A is the ratio of two sides of the triangle. Which two sides? Which ratio is the cosine?The side opposite angle A is BC and the side opposite angle C is AC. The side opposite angle B is AB. So the cosine of angle A is the ratio of the sines of the other two angles.
  • #1
Einstein's Cat
182
2
< Mentor Note -- thread moved to HH from the technical physics forums, so no HH Template is shown >

Say one has the equation of
90= Sin^-1(a) + Sin^-1(b), how would one made the term "b" the subject of such an equation? Please excuse any naivety.
 
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  • #2
1) This belongs in the homework forum
2) You should provide an attempt at the solution.
 
  • #3
Thread closed for Moderation...
 
  • #4
Einstein's Cat said:
Say one has the equation of
90= Sin^-1(a) + Sin^-1(b), how would one made the term "b" the subject of such an equation? Please excuse any naivety.
Thread re-opened for some questions...

@Einstein's Cat -- Where are you getting these math questions from? Is it for schoolwork? Or are you trying to self-study math on your own?

Also, it would help a lot if you would read the tutorial on how to use LaTeX (see Help/How-To under INFO at the top right of the page). It would make it much easier for us to parse the equations you are trying to type into the forum. I'm not sure how to try to parse what you have written above...
 
  • #5
berkeman said:
Thread re-opened for some questions...

@Einstein's Cat -- Where are you getting these math questions from? Is it for schoolwork? Or are you trying to self-study math on your own?

Also, it would help a lot if you would read the tutorial on how to use LaTeX (see Help/How-To under INFO at the top right of the page). It would make it much easier for us to parse the equations you are trying to type into the forum. I'm not sure how to try to parse what you have written above...
It is self- study maths and thank you for the advice
 
  • #6
Einstein's Cat said:
It is self- study maths and thank you for the advice
Why don't you read the LaTeX tutorial, and then show us the equation that you are asking about in LaTeX form. Then also show us what steps you think might be useful for trying to manipulate the equation to isolate the variable you want. Please always show your best efforts when asking questions here at the PF. :smile:
 
  • #7
Einstein's Cat said:
It is self- study maths
Since it is for self-study, it is schoolwork-like. So I will move the thread to the Homework Help forums, where such threads should go. :smile:
 
  • #8
Einstein's Cat said:
< Mentor Note -- thread moved to HH from the technical physics forums, so no HH Template is shown >

Say one has the equation of
90= Sin^-1(a) + Sin^-1(b), how would one made the term "b" the subject of such an equation? Please excuse any naivety.
A pretty obvious answer is that [itex]b= Sin(90- Sin^{-1}(a))[/itex] but that probably isn't what you want-surely you saw that..
 
  • #9
HallsofIvy said:
A pretty obvious answer is that [itex]b= Sin(90- Sin^{-1}(a))[/itex] but that probably isn't what you want-surely you saw that..
That is indeed what I was wanting and so thank you very much for I am completely ignorant of rearranging sin functions in algebraic terms
 
  • #10
Einstein's Cat said:
That is indeed what I was wanting and so thank you very much for I am completely ignorant of rearranging sin functions in algebraic terms
But you can simplify it much more, getting rid of the trig functions entirely.
What is a simpler way of writing sin(90o-x)?
 
  • #11
haruspex said:
But you can simplify it much more, getting rid of the trig functions entirely.
What is a simpler way of writing sin(90o-x)?
I believe Sin(90) is equal to 1
 
  • #12
Einstein's Cat said:
I believe Sin(90) is equal to 1
Yes, but that doesn't help. Consider a right-angled triangle. Let x be one of the other angles. What is the third angle?
Can you find two sides with a ratio of sin(90-x)?
 
  • #13
haruspex said:
Yes, but that doesn't help. Consider a right-angled triangle. Let x be one of the other angles. What is the third angle?
Can you find two sides with a ratio of sin(90-x)?
The other angle would equal 180 -(90+x) and I'm sorry but I do not know the answer to your final question
 
  • #14
Einstein's Cat said:
The other angle would equal 180 -(90+x) and I'm sorry but I do not know the answer to your final question
Consider a triangle ABC. Angle at C is a right angle, so AB is the hypotenuse. Consider angle at A. The sine of A is the ratio of two sides of the triangle. Which two sides? Which ratio is the cosine?
 
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Related to Sine function in equation issue

What is the sine function and how is it used in equations?

The sine function, denoted as sin(x), is a mathematical function that represents the ratio of the side opposite an angle in a right triangle to the hypotenuse. In equations, it is used to model periodic phenomena, such as waves or oscillations, and to find unknown angles or side lengths in triangles.

What is the difference between the sine function and the inverse sine function?

The sine function, sin(x), takes an angle as its input and outputs the ratio of the opposite side to the hypotenuse. The inverse sine function, sin⁻¹(x) or arcsin(x), takes a ratio as its input and outputs the angle that produces that ratio in a right triangle. In other words, the inverse sine function "undoes" the sine function.

How do you graph a sine function?

To graph a sine function, you can plot points by choosing values for the angle (x-value) and calculating the corresponding value of sin(x) (y-value). These points can then be connected to create a smooth, periodic curve. Alternatively, you can use a graphing calculator or online graphing tool to plot the graph automatically.

What are the properties of the sine function?

The sine function has several key properties, including being a periodic function with a period of 360 degrees or 2π radians, having a maximum value of 1 and a minimum value of -1, and being an odd function (sin(-x) = -sin(x)). It also has an inverse function, the inverse sine function, and is one of the three basic trigonometric functions, along with cosine and tangent.

How is the sine function used in real-life situations?

The sine function has many real-life applications, such as in music and sound waves, where it is used to model the vibrations of strings and air molecules. It is also used in physics to describe the motion of pendulums, springs, and other oscillating systems. Additionally, it is used in engineering and architecture to calculate angles and distances in structures and design curves in roads and bridges.

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