## sarahi_smiles 2 years ago Solve 2 - 3 cos x = 5 + 3 cos x for 0 degrees lessthan x lessthan 180 degrees (1 point) can anyone help me...

1. sarahi_smiles

The possible answers are 150 degrees, 30 degrees, 60 degrees, and 120 degrees...?

2. BrittanyFrench

Hey I'm tryin to figure this one out!!

3. sarahi_smiles

Oh ok...if you could help me I would greatly appreciate it!!

4. BrittanyFrench

:) Sure thing. This is geomtry right? Or Algebra 2?

5. sarahi_smiles

I think algebra 2...I'm in precal but shes going over several subject at one time...

6. sarahi_smiles

Like an over view of algebra...

7. yrelhan4

solve the equation. it will give you cosx=-1/2 --> x=120 degrees

8. sarahi_smiles

thanks so much...could you help me answer another question @yrelhan4

9. yrelhan4

cheers! only if i know it.

10. sarahi_smiles

I have to find the angle the normal makes with the positive x-axis....& I have to rewrite it each equation in the normal for and solve the length of the normal... 1. 3x-2y-1=0 2. 5x+y-12=0 3. 4x+3y-4=0

11. sarahi_smiles

If not its ok...but thanks anyway!!!

12. yrelhan4

normal to these lines?

13. sarahi_smiles

Yea..idk what it means either. :/ It said: find the angle the normal makes with the positive x–axis. Hint: You should first rewrite each equation in normal form and solve for the length of the normal.

14. yrelhan4

see that normal from of a line is xsino + ysino =P whee o is angle made with positive x axis and p is the length of normal from origin to the line.

15. yrelhan4

can you find a line perpendicular to the given lines and passing through origin?

16. sarahi_smiles

Ok...no?

17. yrelhan4

slope of a line is -(coefficient of x)/(coefficient of y). and m18m2 =-1 where m1 is the slope of the given line and m2 of the normal. write the normal line in the form of y=mx+c. substitute x,y=0,0 as it passes through the origin. this will give you value of c. plug this value back into the equation. suppose that the line is ax+by+c=0. thelength of perpendicular from x1,y1 is ax1 +by1+c/sqrt(a^2 + b^2). susbtitute 0,0 in place of x1,y1. this will give you value of perpendicular. i am still working on the angle. i seem to know it but cant recall it.

18. yrelhan4

in the first line it is m2*m1=-1

19. sarahi_smiles

If its confusing you & you can't figure it out its ok....I'm just not that good in math lol

20. yrelhan4

just tell me if you get the length of the normal. or i'll you refer you to a site.

21. sarahi_smiles

Can you just refer me....because I'm really confused

22. sarahi_smiles

Sorry...

23. yrelhan4

its alright sweety. i was as poorer at math. chill!! http://answers.yahoo.com/question/index?qid=20090817231959AASOXEf look at this to find the line perpendicular to the given line. and then look at my explanation. and i am not following the hint you gave me. i dont follow it. this method of mine makes more sense to me.

24. yrelhan4

feel free to back to me if any problem.

25. yrelhan4

slope of a line=tano. so arctan[-(coefficient of x)/coefficient of y)] will give you the angle.

26. sarahi_smiles

ok thanks!!!