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Question
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675
1
if tanx = -1/3 and cosx>0
what is:
sin2x
cos2x
tan2x
Guest
Mar 7, 2014
1
+0
Answers
#1
+64
0
Hello
mathao21
!
sinx=(-1/3)/(sqrt(1+(-1/3)^2))
cosx=1/(sqrt(1+(-1/3)^2))
And now, for sin
2x
:
sin2x=2*((-1/sqrt(10))*(3/sqrt(10)))
...for cos
2x
:
cos2x=1-2*(-1/sqrt(10))^2
...for tan
2x
:
tan2x=(2*(-1/3))/(1-((-1/3)^2)))
To sum up:
If tanx=-1/3 and cosx>0 then:
[list]
sin2x=
-3/5
[/*:m]
cos2x=
4/5
[/*:m]
tan2x=
-3/4
[/*:m][/list:u]
Have a nice day!
Dms
Dms
Mar 7, 2014
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