Question

cot (A+B)=cotAcotB-1/cotA+cotB​

Answer 1

Answer:

RS = ((cosA/sinA)(cosB/sinB) -1)/(cosA/sinA + cosB/sinB)

= (cosAcosB/(sinAsinB)-sinAsinB/(sinAsinB)/(sinBcosA + cosBsinA)/(sinAsinB))

= (cosAcosB-sinAsinB)/(sinAsinB)*(sinAsinB)/(sinBcosA + cosBsinA)

= cos(A+B)/sin(A+B)

= cot(A+b)

LHS=RHS, Hence proven

Answer 2

Answer:

Step-by-step explanation:

RS = ((cosA/sinA)(cosB/sinB) -1)/(cosA/sinA + cosB/sinB)

= (cosAcosB/(sinAsinB)-sinAsinB/(sinAsinB)/(sinBcosA + cosBsinA)/(sinAsinB))

= (cosAcosB-sinAsinB)/(sinAsinB)*(sinAsinB)/(sinBcosA + cosBsinA)

= cos(A+B)/sin(A+B)

= cot(A+b)

LHS=RHS, Hence proven