Question

In triangle ABC with B being a right angle, suppose that the sin(A)=.34. Find cos(A).

Answer 1

arcsin(0.34) = A

Answer 2

then take the cosine of that angle

Answer 3

Plenty of nifty ways to do this... is there a way you're familiar with? :)

Answer 4

Calculators aren't strictly necessary, and besides... this question would be far too easy with them :3

Answer 5

I figured it out! Thanks guys

Answer 6

Since it doesn't give you what quad it's in, I'm guessing it doesn't matter if it's positive

Answer 7

That was fast :/

Answer 8

calculators win again, teren

Answer 9

I do not doubt that calculators will make this problem trivial.

Answer 10

I suppose red should stick around as to know how to do it the other way, which is useful :)

Answer 11

Or not :/
Oh well, life goes on... catch you guys later, maybe :3

Answer 12

Wow O.o

Answer 13

Do you want to know how to do it the other way?

Answer 14

sure

Answer 15

sin(A) = (opposite/hypotenuse)
0.34 = 17/50. The opposite side of A is 17, and the hypotenuse is 50.
sin(A) = (17/50)
sin(A) = 0.34

Answer 16

Understand so far?

Answer 17

yeah

Answer 18

cos(A) = adjacent/hypotenuse
cos(A) = x/50.

Under the condition that this is a right triangle, since it is not said that it is oblique, we can find the other side using c^2 = a^2 + b^2, where x = b

Answer 19

Ok

Answer 20

\[50^{2} = 17^{2} - x ^{2}; 2500 = 289 - x; x^2=2211, x=\sqrt{2211}\]

Answer 21

cos(A) = adjacent/hypotenuse
cos(A) = \[\frac{ \sqrt{2211} }{ 50 }\]
arccos(\[\frac{ \sqrt{2211} }{ 50 }\]


= 19.8 degrees = arcsin(.34)

Answer 22

*19.88 degrees

Answer 23

Since both are equal, I know they both are correct.

Answer 24

Ok. Thanks!