Question

学霸帮帮忙，看看这道题，谢谢

Answer 1

6cosx=5tanx=5sinx/cosx,
6cos^2(x)=5sinx
6(1-sin^2(x))=5sinx
6sin^2(x)+5sinx-6=0
6[sin^2(x)+5/6sinx+(5/12)^2]-6-25/24=0
6[sinx+5/12]^2=169/144
sinx+5/12=13/12或sinx+5/12=-13/12
sinx=2/3或sinx=-3/2(舍掉）
p1p22/3