Question

secant square 20 minus cot square 70 diveded by sin square 70 + sin square 20

Answer 1

hi friend

here is your answer
 
=sec^2 20 - cot^2 (90 -20)/sin^2 70 + sin^2(90-70)
=sec^2 20 - tan^2 20 / sin^2 70 +cos^2 70
=1/1
=1

hope it helps

Answer 2

Hey there !!

$\frac{ { \sec }^{2} 20 \: - { \cot}^{2} 70}{ {sin}^{2}70 + {sin}^{2}20 } = \frac{ {sec}^{2}70 - {tan}^{2} 70}{ {sin}^{2}70 + {cos}^{2} 70 } \\ \\ = \frac{1}{1} \\ \\ = 1$
I have used

Note -

Sin² 70 + cos²70 = 1

and sec²70 - tan²70 = 1

Hope this would help you !