Question

If sinX= 0.9, what is the value of cos X? Round the value to the nearest thousandth.

Answer 1

Answer: sqrt(19)/10

Step-by-step explanation:

sinx=0.9

x=arcsin(0.9)

Insert x for cos(x):

cos(arcsin(0.9)=

Use identify $cos(arcsin(x))=\sqrt{1-x^{2} }$, so

$\sqrt{1-(\frac{9}{10})^{2}} =\sqrt{\frac{19}{100} } =\frac{\sqrt{19}}{10}$

Sorry if this is confusing.