Precalculas help
Use the Pythagorean identities to write the expression as an integer.
7sec^2(4y)-7tan^2(4y)
I got 0 and i'm not completly sure if i did it right. thanks
November 5, 2013
Precalculas help
Use the Pythagorean identities to write the expression as an integer.
7sec^2(4y)-7tan^2(4y)
I got 0 and i'm not completly sure if i did it right. thanks
2 Comments • Newest first
[quote=xoqtprincessxo]7/cos^2(4y) - 7sin^2(4y)/cos^2(4y)
(7 - 7sin^2(4y) )/ cos^2(4y)
7(1 - sin^2(4y) / cos^2(4y)
7cos^2(4y) / cos^2(4y)
= 7[/quote]
U gotta use dem pythagorean identities doe!
1 = sin^2(x) + cos^2(x)
multiply by 7 and make x = 4y
7 = 7sin^2(4y) + 7cos^2*(4y)
divide by cos^2(4y)
7sec^2(4y) = 7tan^2(4y) + 7
so 7sec^2(4y) - 7tan^2(4y) = 7tan^2(4y) +7 - 7tan^2(4y) = 7
@Flexography: That awkward moment when your "source" is wikipedia and you don't notice that the TS said "Precalculas".
7/cos^2(4y) - 7sin^2(4y)/cos^2(4y)
(7 - 7sin^2(4y) )/ cos^2(4y)
7(1 - sin^2(4y) / cos^2(4y)
7cos^2(4y) / cos^2(4y)
= 7