Asked by Steve
Find sin 2x if sinx=3/5 and x is in Quadrant II.
Answers
Answered by
Reiny
sinx = 3/5 = opposite/hypotenuse = y/r
and you are in quad II
make a sketch, you should recognize the 3-4-5 Pythagorean triangle, if not ...
x^2 + y^2 = r^2
x^2 + 9 = 25
x = ± 4, but we are in II , so x = -4
cosx = -4/5
sin (2x) = 2sinxcosx = 2(3/5)(-4/5) = -24/25
check it with a calculator to satisfy your curiosity.
and you are in quad II
make a sketch, you should recognize the 3-4-5 Pythagorean triangle, if not ...
x^2 + y^2 = r^2
x^2 + 9 = 25
x = ± 4, but we are in II , so x = -4
cosx = -4/5
sin (2x) = 2sinxcosx = 2(3/5)(-4/5) = -24/25
check it with a calculator to satisfy your curiosity.
There are no AI answers yet. The ability to request AI answers is coming soon!
Submit Your Answer
We prioritize human answers over AI answers.
If you are human, and you can answer this question, please submit your answer.