<Dd> <Table> <Tr> <Td> <P> κ X = k 1 cos 2 ⁡ θ + k 2 sin 2 ⁡ θ . (\ displaystyle \ kappa _ (X) = k_ (1) \ cos ^ (2) \ theta + k_ (2) \ sin ^ (2) \ theta . \,) </P> </Td> <Td> <Table> <Tr> <Td> <P> </P> </Td> <Td> <P> </P> </Td> <Td> <P> </P> </Td> </Tr> <Tr> <Td> <P> </P> </Td> </Tr> </Table> </Td> <Td> <P> (1) </P> </Td> </Tr> </Table> </Dd> <Table> <Tr> <Td> <P> κ X = k 1 cos 2 ⁡ θ + k 2 sin 2 ⁡ θ . (\ displaystyle \ kappa _ (X) = k_ (1) \ cos ^ (2) \ theta + k_ (2) \ sin ^ (2) \ theta . \,) </P> </Td> <Td> <Table> <Tr> <Td> <P> </P> </Td> <Td> <P> </P> </Td> <Td> <P> </P> </Td> </Tr> <Tr> <Td> <P> </P> </Td> </Tr> </Table> </Td> <Td> <P> (1) </P> </Td> </Tr> </Table> <Tr> <Td> <P> κ X = k 1 cos 2 ⁡ θ + k 2 sin 2 ⁡ θ . (\ displaystyle \ kappa _ (X) = k_ (1) \ cos ^ (2) \ theta + k_ (2) \ sin ^ (2) \ theta . \,) </P> </Td> <Td> <Table> <Tr> <Td> <P> </P> </Td> <Td> <P> </P> </Td> <Td> <P> </P> </Td> </Tr> <Tr> <Td> <P> </P> </Td> </Tr> </Table> </Td> <Td> <P> (1) </P> </Td> </Tr> <P> κ X = k 1 cos 2 ⁡ θ + k 2 sin 2 ⁡ θ . (\ displaystyle \ kappa _ (X) = k_ (1) \ cos ^ (2) \ theta + k_ (2) \ sin ^ (2) \ theta . \,) </P>

State and prove euler's theorem in differential geometry