Find the value of tan 3A in terms of tan A

In a triangle ABC, right angled at C, find the value of tan A + tan B in terms of the sides a,b,c.

Find the value of tan 40^@ times tan 50^@ .

Find the values of tan^-1 (tan 5)

Find the value of tan 1^@ tan 2^@ tan 3^@ ….tan 45^@ …..tan 88^@ tan 89^@

Find the value of tan 4^@ tan 43^@ tan 47 ^@ tan 86 ^@

Find the value of tan 20^@ tan 40^@ tan 80^@ .

Find the values of tan 15^@ and tan 75^@

Find the value of sec(tan^-1 (y/2)) in terms of y.

Prove that tan A. (tan 60^(@) +A). Tan (60^(@)-A)=tan 3A and hence find the value of tan 6^(@) tan 42^(@) tan 66^(@) tan 78^(@) .