Express `tan(-1580^@)` in terms of the ratio of a positive angle less than `45^@`.

Find the sum of positive integers less than 400.

Express sin67^@+cos75^@ in terms of trigonometric ratios of angles between 0^@ and 45^@

State which of the following sets are null set or singleton set:the set of positive odd integers less than 3

Express the following set in roster method :{x:x is a prime number less than 8}

Express the following sets using roster method:Set of prime numbers less than 10.

Express tan 15° + cos 15° in terms of angle between 45° and 90° .

Express sin 81° + tan 81° in terms of angle between 0° and 45° .

Express tan theta , sec theta , cot theta in terms of cos theta .

Express the following angles in radian: 45^@

Express sin theta , cos theta , tan theta in terms of cosec theta .