Question

write the value of cot(tan-1 a + cot-1 a).

Answer 1

cot ( tan - 1a + cot - 1a)

= cot ( tan - 2a + cot a)

= cot * tan - 2cot a + cot2 a

[ cot = cos / sin

tan = sin/ cos

Therefore cot*tan = (cos*sin)/(sin*cos)

= 1]

= 1 + cot2 a - 2cot a

[ cot2 a + 1 = cosec2 a ]

= cosec2a - 2cot a

I couldn't get it more further....

Hope this helps.....