Question

if 17 cos A =8,find 15 cosec A-8secB​

Answer 1

Step-by-step explanation:

10sin4x+15cos4x=6,(1)

10sin4x+15cos4x=6(sin2x+cos2x)2

10sin4x+15cos4x=6sin4x+12sin2xcos2x+6cos4x⟹

4sin4x−12sin2xcos2x+9cos4x=0

(2sin2x−3cos2x)2=0⟹

2sin2x−3cos2x=0

2cos2x=3sin2x=2+3cos2x+sin2x=5⟹

2sec2x=3csc2x=5

27csc6x+8sec6x=125+125=250.