Question

which of the following is true?
a. tan^-1 (1) = - cot^-1 (1)
b. tan^-1 (-1)= cot^-1 (1)
c. tan^-1 (-1) = cot^-1 (-1)
d. tan^-1 (1) = cot^-1 (-1)

Answer 1

letter C i got it

Answer 2

i use wolf alpha here every answer make it false unless letter c..i just need a pro who say im wrong or im correct.

Answer 3

yeh sorry I was afk...give me a few mins

Answer 4

no its ok =)

Answer 5

ok, well tan (pi/4)=1 so tan^-1(1)=(pi/4) and similarly, tan(-pi/4)=-1 so tan^-1(-1)=-(pi/4). Also, cot (pi/4)=1 so cot^-1(1)=(pi/4). Similarly, cot(-pi/4)=-1 so cot^-1(-1)=-pi/4. Checking our answers against the above considerations shows that you are correct, c is true.

Answer 6

thanks help a lot