- #1
RoryP
- 75
- 0
Homework Statement
Find the values of the following, without the use of a calculator,
cos(15)+sin(15)
Homework Equations
sin(A±B)= sinAcosB±cosAsinB
cos(A±B)= cosAcosB∓sinAsinB
The Attempt at a Solution
Without the use of a calculator i had to relate back to the 2 triangles which you get the most common values for sin, cos and tan. Namely,
sin(30)= 1/2
cos(30)= √3/2
sin(45)= 1/√2
cos(45)= 1/√2
sin(60)= √3/2
cos(60)= 1/2
sin(0)= 0
cos(0)= 1
sin(90)=1
cos(90)= 0
but i have found no use for any of these, also i didnt think tan was appropriate but I am open to correction! i tried going along the lines of gettting a trig function, with the same angle, to equal 1 so i could use the addition formulae but i had no success!
any help please guys!