Question

sec ²A -tan²A= _ for 0<A>90​

Answer 1

Answer:

It is a identify and it's answer is '1'

Answer 2

Answer:

Class 10 th method:

$sec^{2}A - { \tan }^{2}A = 1$

Identity:

$1 + {tan}^{2} A = {sec}^{2}A$

Class 9th method

sec=H/B

tan=P/B

=(H/B)^2-(P/B)^2

=H^2/B^2-P^2/B^2

=(H^2-P^2)/B^2 {Pythagoras theoram:P^2+B^2=H^2}

=B^2/B^2(cancelled)

=1