(i) Solving,
⇒1−sin230°1−cos230°⇒1−(21)21−(23)2⇒1−411−43⇒4341⇒3×41×4⇒31.
Hence, 1−sin230°1−cos230°=31.
(ii) Solving,
⇒sin 60° cos 30° tan 45°sin 45° cos 45° cos 60°⇒23×23×121×21×21⇒4341⇒31.
Hence, sin 60° cos 30° tan 45°sin 45° cos 45° cos 60°=31.