NDA2011MathematicsTrigonometric Ratios & IdentitiesActual
What is x 1+ x + 1+ x x equal to?
Options
- A2 x
- B2 cosec x
- C2 x
- D2 x
Correct answer
B. 2 cosec x
Step-by-step solution
aligned & x 1+ x + 1+ x x & = ^2 x+(1+ x)^2 x(1+ x) & = ^2 x+1+2 x+ ^2 x x(1+ x) & = ( ^2 x+ ^2 x )+1+2 x x(1+ x) & = 2+2 x x(1+ x) = 2(1+ x) x(1+ x) & =2 cosec x aligned