#### Answer

a) 3
b) 189
c) 479001600

#### Work Step by Step

To find the values of the Euler phi-function, we multiply the integers smaller than the number which are relatively prime to it.
a) $ϕ(4)=3$
b) $ϕ(10)=ϕ(2⋅5)=3⋅7⋅9=189$
c) $ϕ(13)=12!=479001600$

Published by
McGraw-Hill Education

ISBN 10:
0073383090

ISBN 13:
978-0-07338-309-5

a) 3
b) 189
c) 479001600

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