Quantitative Aptitude - Arithmetic Ability Questions

If (cotAcotB - 1) / (cotB + cotA) = x, then the value of x is

In the following question, select the odd word pair from the given alternatives.

What is the value of S = 11x3x5 + 11x4 + 13x5x7 + 14x7 + 15x7x9 + 17x10 + ... upto 20 terms. Then what is the value of S? 

What is the area (in square units) of the figure enclosed by the x-axis, the y-axis and the line x + 2y = 6 ?

If a + b = 17 and a - b = 9 then the value of (4a2 + 4b2) is,

If a2+1=9a, (a≠0) then the value of a2+1a2 is

In the following question, select the related number from the given alternatives.
 
47 : 57 : : 93 : ?

∆DEF is right angled at E. If tanD = 4/3, then what is the value of tanF ?