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If z=4+i, what is 1/z? (in the form a+bi)

1/z =1/(4+i) Multiply both top and bottom by the complex conjugate, z* = 4 - i, 1/z = (4-i)/((4+i)(4-i)) = (4-i)/(16+4i-4i-i²) = (4-i)/17 ans: 4/17 - i/17

Answered by Rachel H. • Further Mathematics tutor

2841 Views

Anouk, Beth and Carlin share £48 between them. Beth gets 3/8 of the money. Anouk and Carlin share the remaining money between them, by the ratio 3:2. How much money does Carlin get?

Beth gets: £48 x 3/8 = £18 The remaining money is: £48 - £18 = £30 (Alternate method: £48 x 5/8 = £30. This eliminates the need for the first step) The ratio is 3:2 so this is the same as fracti...

Answered by Rachel H. • Maths tutor

3196 Views

When do we use haben and when sein with the perfect.

As a general rule, verbs that in the present have an akkusative object form the perfect with haben. The rest with sein. For example:

The table breaks = Der Tisch bricht. [ Subject Nominative: tisch...

Answered by Antonis T. • German tutor

2299 Views

A truck with mass 1200kg is moving at 8m/s when it collides head-on with a stationary car of mass 800kg. As they collide, the vehicles move together with the same velocity, v. Calculate this velocity.

Momentum is conserved. MU + mu = (M+m)v (1200 x 8) + (800 x 0) = (1200 + 800)v 9600 = 2000v v = 9600/2000 = 4.8m/s

Answered by Rachel H. • Physics tutor

6773 Views

What does reversible mean?

Reversible is a term used for certain reactions that never reach a final stage. So imagine we have A and B reacting together to form C, and we say that this reaction is reversible. So at a point in time, ...

Answered by Antonis T. • Chemistry tutor

2557 Views