Question

tan (a) =17÷18, tan (b) =1÷35 then find the value of cos (a+b)​

Answer 1

Answer:

Step-by-step explanation:

tan A = 18/17 & tan B = 1/35

tan A - tan B = [18/17 - 1/35] = [18 x35 - 17]/(17 x 35) = 630/595

and (1 + tan A.tan B) = 1 + 18/(17 x 35) = [17 x 35 + 18]/(17 x 35)

= 613/595

Now, tan (A - B) = (tan A - tan B)/(1 + tan A.tan B)  

= [630/595]/[(630)/(595)]

= [630/595] * [(595)/(630)]

= 1

= tan 45  

=> A - B = 45 (deg.)

and tan (A - B) = 1 = tan 225

=> A - B = 225(deg.)

A - B = 45 , 225 (deg.) <==ANSWER

Hope i helped u :)

Answer 2

Answer:

Step-by-step explanation:

tan(a)=sin(17)/cos(18),tan(b)=sin(1)/cos(35),cos(a+b)=cos(18+35)=0.602