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# max value of arg(z) watch

1. Does anyone know how to do this Q by finding max arg(z)

Given that |z - 5 + 7i| = 5

I've drawn it on an argand diagram but still not sure how to work out max arg(z)

Any help would be greatly appreciated. Thanks.
2. (Original post by abdul h)
Does anyone know how to do this Q by finding max arg(z)

Given that |z - 5 + 7i| = 5

I've drawn it on an argand diagram but still not sure how to work out max arg(z)

Any help would be greatly appreciated. Thanks.
Draw a line from the origin to the circle such that it touches the circle and the argument between that line and the x-axis is greatest. Mark that angle and this is what you want to find.
3. (Original post by RDKGames)
Draw a line from the origin to the circle such that it touches the circle and the argument between that line and the x-axis is greatest. Mark that angle and this is what you want to find.
By drawing a tangent from origin to touching the circle when theta is greatest. Wouldn't arg(z) be found by measuring anticlockwise by
4. (Original post by abdul h)
By drawing a tangent from origin to touching the circle when theta is greatest. Wouldn't arg(z) be found by measuring anticlockwise by
What?
5. (Original post by RDKGames)
What?
Sorry I was meant to say measuring anti-clockwise from positive real axis.
6. (Original post by abdul h)
Sorry I was meant to say measuring anti-clockwise from positive real axis.
Yes it would be, but you need to find it's exact value.

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