Help me prove that sec(a-b) =seca*secb/1+tana*tanb

Use:

See below.

Step-by-step explanation:

Write the sec's as 1 / cos  and the tan's as sin / cos

I will write sin as s and cos as c:

Left side  =  1 / ( cos)a - b)  =     1  / (ca cb + sa sb)

Right side =    1  /  (  ca cb ( 1 + sa sb / ca cb))

=  1 / ( ca cb *  ( ca cb + sa sb) / ca cb)

The 'ca cb' cancels out so

Right side = 1 / (ca cb + sa sb)  = left side..

130.66 for edgedunity students

the answer to this would be 5x^3-6x^2-24 over 3x^2

hope this if needed hmu