Question

if sinA sin B - CosA cosB + 1= 0 then prove that 1+ cotA tan B = 0​

Answer 1

Answer:

-(cosAcosB-sinAsinB)=-1

Step-by-step explanation:

cos(A+B)=1

:.A+B=0 degrees

(cotA= cosA/sinA

tanB=sinB/cosB)

1+cotAtanB= 1+cosAsinB/sinAcosB

=sinAcosB+cosAsinB/sinAcosB

=sin(A+B)/sinAcosB=sin0/sinAcosB

=0 /sinAcosB=0

Hence,proved