Question

If sin x = .21,what is cos x?

Answer 1

I would do it like this.
\[\sin x = .21\]\[\sin ^2x = (.21)^2\]
\[We~~know~~that:~~Cos^2x=1-Sin^2x~~~~~~S O,~...\]\[\sin ^2x = (.21)^2~~~~~~->~~~~~-\sin^2x=-(.21)^2\]
\[1-\sin^2x=\cos^2x~~~~~~~Sub,~~i n~~~~-(.21)^2~~~for~~~-\sin^2x\]\[1-(.21)^2=\cos^2x\]
I think you got it from here...This isn't a good approach.. I am tired -:(

Answer 2

.98

Answer 3

How do you get it ?

Answer 4

21^2 + a^2 = 100^2
a^2 = 100^2 - 21^2
a^2 = (100 - 21)(100 + 21)
a^2 = 79 x 121
a^2 = 9559
a = sqrt (9559) = 97.77...
Cos x = a/h = 97.77.. / 100
Cos x = 0.977777...
Cos x = 0.98

Answer 5

Okay !

Answer 6

i did good right?

Answer 7

Yes