# Trig equation - graphing to show solutions

• May 1st 2008, 07:47 AM
sux@math
Trig equation - graphing to show solutions
a) use special triangles and CAST rule to solve 2 sin x + sqrt3 for 0 to 360 deg. Good, I got that: 60 deg & 120 deg

b) What feature of the graph, in the form y=a sin x + b would show the solutions? According to my book & if I understand correctly, it is the the repeated numeric value along the graph that equals 60 deg BUT - see c)

c) Draw the graph and use it to show the solutions. THIS I am not sure about - do I graph 2 sin x + sqrt3, OR y=sinx and then show the translation?

I can create a table of x & y values to plot for 2 sin x +sqrt3 - so is that where I start? And is there a standard way of setting up your graph, so that say along the x-axis I start with 30 deg & go up by 30 deg intervals?

(Sorry, I know I am asking a lot. But, I am just a future graphic designer trying to fill a prerequisite so I don't get kicked outta my program - yeah, I would die.)
• May 1st 2008, 08:31 AM
Moo
Hello,

Quote:

Originally Posted by sux@math
a) use special triangles and CAST rule to solve 2 sin x + sqrt3 for 0 to 360 deg. Good, I got that: 60 deg & 120 deg

So I suppose it was 2 sin x+sqrt 3=0 ?

Quote:

b) What feature of the graph, in the form y=a sin x + b would show the solutions? According to my book & if I understand correctly, it is the the repeated numeric value along the graph that equals 60 deg BUT - see c)
Not really... Previously, you have solved for x in y=0 (assuming that a=2 and b=sqrt 3). So you got the points where the graph intersects the x-axis.

Quote:

c) Draw the graph and use it to show the solutions. THIS I am not sure about - do I graph 2 sin x + sqrt3, OR y=sinx and then show the translation?
I think you have to graph 2sin x+sqrt 3, since you want to retrieve the solutions of the first equation. It's easier to find points in the x-axis than points which have sqrt 3/2 as ordinate.

Quote:

I can create a table of x & y values to plot for 2 sin x +sqrt3 - so is that where I start? And is there a standard way of setting up your graph, so that say along the x-axis I start with 30 deg & go up by 30 deg intervals?
I don't really understand what you wanted to do.
Actually, the graph will be like sin x, but it's 2 sin x (the shape will be quite similar) and then, adding sqrt 3 is like if you elevate the graph (you add sqrt 3 to each ordinate).

Quote:

(Sorry, I know I am asking a lot. But, I am just a future graphic designer trying to fill a prerequisite so I don't get kicked outta my program - yeah, I would die.)
Why being sorry ? :o