hence,
also,
hence,
if tan x=5/3
a) What is the value of sin (2x)
b) What is the value of cos (2x)
my awnser have to be in fraction
Im not allowed to use a calculater to get an awnser and im unsure what im suppose to do...
I think that sin x=5
and cos x=3
but i really don't know...
Thanks in advance
Janne the Swede
I was unable to correctly use your way of getting cos2x
I tested it on another question.
tan(x)=1/7
find a. a*cos(2x)
=>
((1*cosx)/7)²+cos²x=1
2cos²x=49
and i just saw what I did wrong... i forgot to multiply the ...+cos²x with 49.. nm xD
after i got 50cos²x=49
is the awnser then cos2x+1=7
=cos2x=-6/25
or did I do it wrong somewhere?