KVPY2014MathematicsTrigonometric Equations
The number of solutions to the equation ⁴ x+ 1 ² x = ⁴ x+ 1 ² x in the interval [0,2 ] is :
Options
- A6
- B4
- C2
- D0
Correct answer
B. 4
Step-by-step solution
⁴ x- ⁴ x= 1 ² x - 1 ² x ( ² x- ² x )= ( ² x- ² x ) ² x ² x 2 x= 4 2 x ² 2 x 2 x (1-4 cosec ² 2 x )=0 2 x=02 x=2 n 2 x=n 4 At n=0, x= 4 n=1 ; x= 5 4 , 3 4 n=2, x= 7 4