( ( ( The product ) ( of ( ( ( the frequency ) and ) ( the wavelength ) ) ) ) ( ( is ( equal ( to ( ( the speed ) ( of ( sound ( in ( the medium ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (NN product)) (PP (IN of) (NP (NP (DT the) (NN frequency)) (CC and) (NP (DT the) (NN wavelength))))) (VP (VBZ is) (ADJP (JJ equal) (PP (TO to) (NP (NP (DT the) (NN speed)) (PP (IN of) (NP (NP (NN sound)) (PP (IN in) (NP (DT the) (NN medium))))))))) (. .)))
The product of the frequency and the wavelength is equal to the speed of sound in the medium.
(ROOT (S (NP (NP (DT The) (NN product)) (PP (IN of) (NP (NP (NP (DT a) (NN wave) (POS 's)) (NN wavelength)) (CC and) (NP (PRP$ its) (NN frequency))))) (VP (VBZ is) (NP (PRP$ its) (NN speed))) (. .)))