Math, asked by Simran200211, 1 year ago

(secA - cosA) (secA + cosA) = sin²A + tan²A

HeY MaTeS!!!
its ReALLy confusing me very much plzz help...


Simran200211: where i go????
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Answers

Answered by Tamash
2
Hi mate here is ur query..

************

Given LHS

=(secA - cosA) (secA + cosA)

since (a+b)(a-b)=a²-b²

hence

=sec²A-cos²A

=(1+tan²A)-(1-sin²A)


=Sin²A+tan²A=RHS

proved

***********

Hope this will help you.

Simran200211: thank u
Tamash: pleasure☺☺
Simran200211: :-)
Answered by ankitmeena7
3
(secA +cosA)(secA - cosA) 
= sec²A - cos²A <difference of 2 squares> 
= 1/cos²A - cos²A 
= 1/cos²A - cos^4A/cos²A 
= (1 - cos^4A)/cos²A 
= (1-cos²A)(1+cos²A)/cos²A 
= sin²A(1+cos²A)/cos²A 
[sin²A/cos²A](1+cos²A) 
= [sin²A/cos²A] + [sin²A/cos²A]cos²A 
= sin²A/cos²A + sin²A 
= tan²A + sin²A.
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