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# Trig question C2 HELP! watch

1. The question

CosX=0.7

X=Cos^-1(0.7) = 45.6 (3 sig fig)

Using cast can someone tell me if this is right with a -360<x<360 interval

I got 45.6, -45.6, 314.4, - 314.4

Is that right ?
2. Yes your solutions are correct.

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3. (Original post by SherlockHolmes)

This was posted from The Student Room's iPhone/iPad App
Is this right for an interval of -180<x<180

Tan2X=1.2 _________> -360 <x<360
X=Tan^-1(1.2)

2X = 50.2, -50.2 230.2,-230.2
X= 25.1, -25.1, 115.1, -115.1 ?
4. (Original post by User32432432)
Is this right for an interval of -180<x<180

Tan2X=1.2 _________> -360 <x<360
X=Tan^-1(1.2)

2X = 50.2, -50.2 230.2,-230.2
X= 25.1, -25.1, 115.1, -115.1 ?
hm your solutions are correct but I'm a little confused; is x in the interval -180 < x < 180 or -360 < x < 360 ?
5. (Original post by User32432432)
Is this right for an interval of -180<x<180

Tan2X=1.2 _________> -360 <x<360
X=Tan^-1(1.2)

2X = 50.2, -50.2 230.2,-230.2
X= 25.1, -25.1, 115.1, -115.1 ?

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