Question

If sin a sin B - cos a cos B +1=0, then prove that cot a tan b = -1​

Answer 1

Answer:

sinAsinB-cosAcosB +1=0

divided by cosAsinB

sinAsinB-cosAcosB +1/cosAsinB=0

cosAsinB cosAsinB

tanA-cotB +1/cosAsinB=0

so, cot A tan B = -1