(1+sinx)/cosx= -1/2(sinx/2+cosx/2)²/(cosx/2) ²-(sinx/2)²=-1/2(sinx/2+cosx/2)/(sinx/2-cosx/2)=1/2sinx/2=-3cosx/2sinx/2=-3/√10cosx/2=1/√10sinx=-3/5