KVPY2012MathematicsApplication of Derivatives
Let n be a natural number and let 'a' be a real number. The number of zeros of x ^ 2 n +1 -(2 n +1) x + a =0 in the interval [-1,1] is -
Options
- A2 if a >0
- B2 if a < 0
- CAt most one for every value of a
- DAt least three for every value of a
Correct answer
C. At most one for every value of a
Step-by-step solution
array l f(x)=x^ 2 n+1 -(2 n+1) x+a f^ (x)=(2 n+1) x^ 2 n -(2 n+1) array =(2 n+1) (x^ 2 n -1 ) < 0 when x [-1,1] f ( x ) is strictly decreasing in [-1,1] f ( x ) cut x axis at most one point in given interval