AP EAMCET202017 Sep 2020Morning ShiftMathematicsTrigonometric Ratios & IdentitiesActual
If ( (x)= 1 3 ), then ( (3 x) ) is
Options
- A( 8 9 )
- B( 7 9 )
- C1
- D( 2 3 )
Correct answer
B. ( 7 9 )
Step-by-step solution
( aligned & (x)= 1 3 , (3 x)=? & e^x-e^ -x e^x+e^ -x = 1 3 2 e^x=4 e^ -x (e^ 2 x =2 ) & and (3 x)= e^ 3 x -e^ -3 x e^ 3 x +e^ -3 x = (e^ 2 x )^3-1 (e^ 2 x )^3+1 = 8-1 8+1 = 7 9 aligned )