If tan α = 2, then the value of   $$ {cosec^2 α - sec^2 α}\over{cosec^2 α + sec^2 α}   $$ is : 

A shopkeeper has 11 books of same cost price. He sells the first book at certain price, then he sells second book at a price which is ₹ 1 less than the selling price of first book and then he sells third book at a price which is ₹1 less than the selling price of second book. Following this pattern, he sold all 11 books. If he sells sixth book at its cost price. Find the overall percent profit or loss on selling all 11 books. 

Out of the given responses one of the factors of  (a²-b²)³+(b²-c²)³+(c²-a²)³ is 

x = y = 333 and z = 334, then value of x³ + y³ + z³ – 3xyz is 

If a + b + c = 0, then a³+b³+c³ is equal to 

If 2sin² θ – 3 sin θ + 1 = 0,   θ being positive angle, then the values of θ are : 

The value of sec⁴ A (1 – sin⁴A) – 2tan²A is: 

A man buys a table and a chair for 500. He sells the table at a loss of 10 % and the chair at a gain of 10 %. He still gain ₹10 on the whole. The cost price of chair in rupees is