Question

If 7 sin2A +3 cos2A= 4 , prove that tan A=1/√​

Answer 1

Answer:

7sin2x+3cos2x=4

4sin2x+3sin2x+3cos2x=4

4sin2x+3=4

4sin2x=1

sin2x=41

sinx=21 or sinx=−21 

Taking the positive root

x=6π

tan(6π)=31

Hence proved.