三角學角度--Pi/10

cos(pi/(10))

=

1/4sqrt(10+2sqrt(5))

cos((3pi)/(10))

=

1/4sqrt(10-2sqrt(5))

cot(pi/(10))

=

sqrt(5+2sqrt(5))

cot((3pi)/(10))

=

sqrt(5-2sqrt(5))

csc(pi/(10))

=

1+sqrt(5)

csc((3pi)/(10))

=

sqrt(5)-1

sec(pi/(10))

=

1/5sqrt(50-10sqrt(5))

sec((3pi)/(10))

=

1/5sqrt(50+10sqrt(5))

sin(pi/(10))

=

1/4(sqrt(5)-1)

sin((3pi)/(10))

=

1/4(1+sqrt(5))

tan(pi/(10))

=

1/5sqrt(25-10sqrt(5))

tan((3pi)/(10))

=

1/5sqrt(25+10sqrt(5)).

sin(pi/(10))

=

sin(1/2·pi/5)

=

sqrt(1/2[1-cos(pi/5)])

=

sqrt(1/2[1-1/4(1+sqrt(5))])

=

1/4(sqrt(5)-1)

cos(pi/(10))

=

cos(1/2·pi/5)

=

sqrt(1/2[1+cos(pi/5)])

=

sqrt(1/2[1+1/4(1+sqrt(5))])

=

1/4sqrt(10+2sqrt(5))

tan(pi/(10))

=

sqrt((3-sqrt(5))/(5+sqrt(5)))

=

1/5sqrt(25-10sqrt(5)).