If sin θ =a/b, then cos θ is equal to

If cos A= 4/5, then the value of tan A is?

The value of the expression cosec(75⁰+ θ)-sec(15⁰- θ)-tan(55⁰+ θ)+cot(35⁰- θ) is

If ABC is right angled at C, then the value of cos (A+B) is

The value of (tan 1°. tan 2°.tan 3° …… tan 89⁰⁾ is