The “Nutrient Index” concept in soil fertility

Find the simplified value of:

(tan 40 º  +  tan 20 º )/(1 -  tan 40 º  tan 20 º)

What is the value of cos75°? 

sin² 12˚ + sin² 14˚ + sin² 16˚ + sin² 18˚ + ……… + sin² 78˚ =?

If Sin 3A = Cos (A - 46°) where 3A is acute angle, then the Value of A is

sin² 17˚ + sin² 19˚ + sin² 21˚ + sin² 23˚ + ……… + sin² 77˚ = ?

What is the value of sin (B – C) cos (A – D) + sin (A – B) cos (C – D) + sin (C – A) cos (B – D)?

If tan 3.5θ x tan 6.5θ = 1 then the value of tan 5θ is

Take  θ = 45⁰

(cos5°+sin5°)/(cos5°-sin5°) is equal to: