JEE Main20254 Apr 2025Morning ShiftMathematicsTrigonometric EquationsActual
If 10 ^4 +15 ^4 =6 , then the value of 27 cosec ^6 +8 ^6 16 ^8 is:
Options
- A2 5
- B3 4
- C3 5
- D1 5
Correct answer
A. 2 5
Step-by-step solution
aligned & 10 ( ^2 )^2+15 (1- ^2 )^2=6 & Let ^2 = t 10 t ^2+15(1- t )^2=16 & 10 t ^2+15-30 t +15 t ^2=6 & 25 t ^2-30 t +9=0 & (5 t -3)^2=0 & ^2 = 3 5 and ^2 = 2 5 & 27 125 27 +8+ 125 8 16 ( 5 2 )^4 = 250 125 5 = 2 5 aligned