A community for students.
Here's the question you clicked on:
 0 viewing
CEBS95
 3 years ago
tan^2(60) + 4cos^2(45)  9tan^2(30)  8sin^2(30)
The answer is zero but why!? i need step by step solution please
CEBS95
 3 years ago
tan^2(60) + 4cos^2(45)  9tan^2(30)  8sin^2(30) The answer is zero but why!? i need step by step solution please

This Question is Closed

Shadowys
 3 years ago
Best ResponseYou've already chosen the best response.0why can't you just plug the whole thing into your calculator?

CEBS95
 3 years ago
Best ResponseYou've already chosen the best response.0because in the exam they already give you the answer, you have to do the procedure

Callisto
 3 years ago
Best ResponseYou've already chosen the best response.2tan60 = \(\sqrt{3}\) cos45 = \(\frac{1}{\sqrt2}\) tan30 = \(\frac{1}{\sqrt3}\) sin30 = 1/2 These are all special angles and you should remember them.

CEBS95
 3 years ago
Best ResponseYou've already chosen the best response.0yes i know them but i just continue to get 6 instead of 0

Shadowys
 3 years ago
Best ResponseYou've already chosen the best response.0I'm getting zero just fine though. note the squares.

CEBS95
 3 years ago
Best ResponseYou've already chosen the best response.0tan^2(60) = 3 ? 4cos^2(45) = 4 ?

Callisto
 3 years ago
Best ResponseYou've already chosen the best response.24cos^2(45) = 4 (1/2) = ...?

CEBS95
 3 years ago
Best ResponseYou've already chosen the best response.0my math base is not good, that's the reason i wrote step by step solution

Callisto
 3 years ago
Best ResponseYou've already chosen the best response.2\[cos45 =\frac{1}{\sqrt2}\]\[cos^245 =(\frac{1}{\sqrt2})^2 = \frac{1}{2}\]\[4cos45 =4(\frac{1}{2}) = ...?\]

winterfez
 3 years ago
Best ResponseYou've already chosen the best response.0\[\frac{ \sin ^{2} (60)}{ \cos ^{2}(60)}+4\cos ^{2}(45)9\frac{ \sin ^{2}(30) }{ \cos ^{2}(30) }8\sin ^{2}(30)\]

winterfez
 3 years ago
Best ResponseYou've already chosen the best response.0dw:1355048071288:dw

CEBS95
 3 years ago
Best ResponseYou've already chosen the best response.0i found in my book that cos 45 = \[\frac{ \sqrt{2} }{ 2}\]

Callisto
 3 years ago
Best ResponseYou've already chosen the best response.2\[\frac{1}{\sqrt2}=\frac{1}{\sqrt2}\times \frac{\sqrt2}{\sqrt2}=\frac{\sqrt2}{\sqrt2^2} = \frac{\sqrt2}{2}\] Just rationalization.

CEBS95
 3 years ago
Best ResponseYou've already chosen the best response.09tan^2(30) = \[\tan( 30) = \frac{ \sqrt{3} }{ 3 } ; \tan ^{2}(30) = 3/9 = 1/3 \]

CEBS95
 3 years ago
Best ResponseYou've already chosen the best response.09tan^2(30)  8sin^2(30) = 3  8 = 5, at the end that will give me 5 (5) that equals 10

Callisto
 3 years ago
Best ResponseYou've already chosen the best response.28 sin ^2 (30) = 8 (1/2)^2 = 8 (1/4) = ...

winterfez
 3 years ago
Best ResponseYou've already chosen the best response.0dw:1355049445375:dw look at this one to see how i get 0

Callisto
 3 years ago
Best ResponseYou've already chosen the best response.2tan^2(60) + 4cos^2(45)  9tan^2(30)  8sin^2(30) tan^2(60) = \(\sqrt3^2\) = ... 4cos^2(45) = 4\((\frac{1}{\sqrt2})^2\) = 4(1/2) = ...  9tan^2(30) = 9 \((\frac{1}{\sqrt3})^2\) = 9 (1/3) = ...  8sin^2(30) = 8 (1/2)^2 = 8 (1/4) = ... Sum up the four answers.

winterfez
 3 years ago
Best ResponseYou've already chosen the best response.0dw:1355049643294:dw

CEBS95
 3 years ago
Best ResponseYou've already chosen the best response.0zero! nice thanks calisto

Callisto
 3 years ago
Best ResponseYou've already chosen the best response.2 30  45  60  sin  \(\frac{1}{2}\)  \(\frac{1}{\sqrt2} /\frac{\sqrt2}{2} \)  \(\frac{\sqrt3}{2}\)  cos  \(\frac{\sqrt3}{2}\)  \(\frac{1}{\sqrt2} /\frac{\sqrt2}{2} \)  \(\frac{1}{2}\)  tan  \(\frac{1}{\sqrt3} /\frac{\sqrt3}{3} \)  1  \(\sqrt{3}\)

CEBS95
 3 years ago
Best ResponseYou've already chosen the best response.0yes, with practice i will memorise the terms
Ask your own question
Sign UpFind more explanations on OpenStudy
Your question is ready. Sign up for free to start getting answers.
spraguer
(Moderator)
5
→ View Detailed Profile
is replying to Can someone tell me what button the professor is hitting...
23
 Teamwork 19 Teammate
 Problem Solving 19 Hero
 Engagement 19 Mad Hatter
 You have blocked this person.
 ✔ You're a fan Checking fan status...
Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.