Question

if 7 sin2A +3cos2A = 4 show that tanA = 1/3

Answer 1

7sin²A + 3(1-sin²A)= 4

7sin²A + 3-3sin²A = 4

4sin²A = 4-3

sin²A = 1/4

sinA =√1/4 = 1/2

sin30°=1/2

A = 30°

tan30° = 1/√3

tanA = 1/√3