Question

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

Answer 1

why can't you just plug the whole thing into your calculator?

Answer 2

because in the exam they already give you the answer, you have to do the procedure

Answer 3

tan60 = \(\sqrt{3}\)
cos45 = \(\frac{1}{\sqrt2}\)
tan30 = \(\frac{1}{\sqrt3}\)
sin30 = 1/2
These are all special angles and you should remember them.

Answer 4

yes i know them but i just continue to get 6 instead of 0

Answer 5

I'm getting zero just fine though. note the squares.

Answer 6

tan^2(60) = 3 ?
4cos^2(45) = 4 ?

Answer 7

4cos^2(45) = 4 (1/2) = ...?

Answer 8

my math base is not good, that's the reason i wrote step by step solution

Answer 9

\[cos45 =\frac{1}{\sqrt2}\]\[cos^245 =(\frac{1}{\sqrt2})^2 = \frac{1}{2}\]\[4cos45 =4(\frac{1}{2}) = ...?\]

Answer 10

4 (1/2) = 2

Answer 11

Yes.

Answer 12

\[\frac{ \sin ^{2} (60)}{ \cos ^{2}(60)}+4\cos ^{2}(45)-9\frac{ \sin ^{2}(30) }{ \cos ^{2}(30) }-8\sin ^{2}(30)\]

Answer 13

so, tan^2(60) = 3

Answer 14

tan^2(60) = 3 <- Yes