Trigonometry problem
- Thread starter jjherriot
- Start date
D
Deleted member 4993
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start with sin(α-ß) = sin(α)*cos(ß) - cos(α)*sin(ß) and continue.......Please share your work with us .
If you are stuck at the beginning tell us and we'll start with the definitions.
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Trig problem continued with workings
I need to prove that ab is
= h.sin(A-B)/sin A.sin B
I used sine rule twice to get cb and ca. If I subtract these I will get ab.
The red highlighted section is cb which I am subtracting from ca.
So far I have got to;
h.sin90-B/sinB -h.sin90-A/sinA then....
sinA(h.sin(90-B)-sinB(sin90-A) / sinA.sinB
This is where I get stuck. Apparently I need to change something into a cos value but I am not sure how or why to do this.
Any help in solving this is greatly appreciated. Thank you!
I need to prove that ab is
= h.sin(A-B)/sin A.sin B
I used sine rule twice to get cb and ca. If I subtract these I will get ab.
The red highlighted section is cb which I am subtracting from ca.
So far I have got to;
h.sin90-B/sinB -h.sin90-A/sinA then....
sinA(h.sin(90-B)-sinB(sin90-A) / sinA.sinB
This is where I get stuck. Apparently I need to change something into a cos value but I am not sure how or why to do this.
Any help in solving this is greatly appreciated. Thank you!
D
Deleted member 4993
Guest
sin(90° - Θ) = cos(Θ)
Thank you! I have got it now! Thanks!