Friday, March 18, 2011

tan sin and cos examples, problems

How to punch in tan, cos, sin and the angle:
Press either the angle or the ratio first than the other and the answer comes up usually in a very small number like,  tan20=0.36397023426620236135104788277683

A hiker(b) is looking down at city at a 76 degree angle, what is the distance of the cities length (opposite). say we know the adjacent (1223 ft), and we need to know the length of opposite so the equation for opposite and adjacent is tangent (tan=o/a) so then all we do is tan 76 and multiply that by 1223 which is the adjacent.

Then we get 4905.2 ft as the opposite. Which is the length of the city.  
 (forget 76 as angle for b)Say we dont know angle c but we know each side of the triangle: (ac=10, ab=15, bc=18).  Say that we need to find angle c.  So we can use two of the three terms, tan or sin.  We will use tan so that is the adjacent and the oppoisite of the angle, ac=10 and ab=15.  So the inverse of tan to cancel tan. So the equation to solve it tan-1=15/10 which 56.3.
Now say we dont know the hypotenuse but we have the adjacent side to c, adjacent(10) over hypotanuse would be cos.  The equation would be cos56.3=10/h so to solve we would it be 18.

Thursday, March 17, 2011

right triangles and sine, cosine and tangent

 The ratio of the opposite side of a right triangle to the hypotenuse the sine and give it the symbol
sin = o / h
The ratio of the adjacent side of a right triangle to the hypotenuse is called the cosine and given the symbol
cos = a / h
Finally, the ratio of the opposite side to the adjacent side is called the tangent and given the symbol
tan = o / a
If we knew at least one of each part of the ratio we could find the answer.

tang wavelength is the green

green line is y=tan(x), black line is y=sin(x), red isy=cos(x)

Wednesday, March 16, 2011

graphing sin

blue and pink are from original comparing to black(y=7sin(x) and red(y=sin(7x).