Question

If sin^(4)A-cos^(4)A=1 and 0<A<=90^(@) then A=​

Answer 1

Answer:

90°

Step-by-step explanation:

(sin^2A)^2 - (cos^2A)=1

(sin^2 A+cos^2 A)(sin^2 A - cos^2 A) = 1

=> 1× (sin^2 A - cos^2 A)= sin^2 A+ cos^2 A

=> sin^ 2 A cancel from each side

=> 0 = 2 cos^2 A

=> cosA =0= cos 90°

so A = 90°