Ok so this week we learned about vectors and some other stuff i dont really remember..ANNYYYWAYY..one thing i know is whether vectors are orthogonal or parallel. there are a few formluas to figure out if they are orthogonal..4 to be exact..
1. u . v= v . u
2. u . u= /u/^2
3. k(u . v)= (ku) . v
4. u . (v+w)= u . v+ u . w
It is orthogonal if it equals 0.
Ok so i forget alot of trig stuff like law of sines and law of cosines so i need help with that
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1.Law of Sines(used to non-right triangles):
ReplyDeleteSin A/a = Sin B/b= Sin C/c
Example: you have a triangle with the sides 4 and 5 & you also have an angle of 30 degrees.
A = 1/2 (4) (5) Sin 30 degrees
A = 10 Sin 30 degrees which is aproximately = 5
2.) Law of Cosines (used when you can't use Law of Sines):
(opposite leg)^2 = (adjacent leg)^2 + (other adjacent leg)^2 - 2(adjacent leg) (adjacent leg) cos (angle between)
Example: you have a triangle with the sides of 5, 6, and 7. find the angle between 5 and 6.
7^2=6^2+5^2-2(5)(6)
cos a7^2-6^2-5^2= 2(5)(6)
cos acos a= 7^2-6^2-5^2 / -2(6)(5)
a= cos-1 ((7^2-^6^2-5^2)/(-2(5)(6))
a= 78.463 degrees
i hope that helps stephen...
law of sine is a formula used to solve for the components of a triangle when there is a set or pair of information given meaning a length of a side on the opposite side of a given angle.
ReplyDeletelaw of cosines is a formula used to solve for the components of a triangle when a set or pair of information is not given.