SOLUTION: i don't get the concept of exact trigonometric value so the problem is sin(data) =2/5 0degrees<(data)< 90degrees cos(data)=? please show all work and if possible, please

Algebra ->  Trigonometry-basics -> SOLUTION: i don't get the concept of exact trigonometric value so the problem is sin(data) =2/5 0degrees<(data)< 90degrees cos(data)=? please show all work and if possible, please       Log On


   



Question 683572: i don't get the concept of exact trigonometric value
so the problem is
sin(data) =2/5
0degrees<(data)< 90degrees
cos(data)=?
please show all work and if possible, please explain how to solve these kind of problems

Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
sin(data) =2/5
0degrees<(data)< 90degrees
cos(data)=?
-------
sin(angle) = y/r
------------------------
Since sin(data) = 2/5,y = 2 and r = 5
----
Solve for "x" using r^2 = x^2+y^2
---
x = sqrt[r^2-y^2] = sqrt[25-4] = sqrt(21)
-----
Your Problem:
cos(data) = x/r = sqrt(21)/5
====================================
Cheers,
Stan H.