Asked by Anonymous
use sum or difference identities to find the exact value of the trigonometric function: tan 345
please show work, i cant figure out what im doing wrong!
please show work, i cant figure out what im doing wrong!
Answers
Answered by
bobpursley
tan(345)?
Tan(2*345)=tan(690)=tan(720-30)=tan(-30)
tan(2*345)= 2*tan(345)/(1-tan^2(345)
lets call tan(345) Y
tan(-30)=2y/(1-y^2)
Call Tan(-30) X
x-XY^2=2Y
XY^2+2Y-x=0
use the quadratic to solve for y in terms of X
(tan(-30)=-1/sqrt3)
Tan(2*345)=tan(690)=tan(720-30)=tan(-30)
tan(2*345)= 2*tan(345)/(1-tan^2(345)
lets call tan(345) Y
tan(-30)=2y/(1-y^2)
Call Tan(-30) X
x-XY^2=2Y
XY^2+2Y-x=0
use the quadratic to solve for y in terms of X
(tan(-30)=-1/sqrt3)
Answered by
mostafa
prove that tan20 tan30 tan40 = tan 10