anonymous
  • anonymous
given sinx=-1/4 and 180
Mathematics
  • Stacey Warren - Expert brainly.com
Hey! We 've verified this expert answer for you, click below to unlock the details :)
SOLVED
At vero eos et accusamus et iusto odio dignissimos ducimus qui blanditiis praesentium voluptatum deleniti atque corrupti quos dolores et quas molestias excepturi sint occaecati cupiditate non provident, similique sunt in culpa qui officia deserunt mollitia animi, id est laborum et dolorum fuga. Et harum quidem rerum facilis est et expedita distinctio. Nam libero tempore, cum soluta nobis est eligendi optio cumque nihil impedit quo minus id quod maxime placeat facere possimus, omnis voluptas assumenda est, omnis dolor repellendus. Itaque earum rerum hic tenetur a sapiente delectus, ut aut reiciendis voluptatibus maiores alias consequatur aut perferendis doloribus asperiores repellat.
chestercat
  • chestercat
I got my questions answered at brainly.com in under 10 minutes. Go to brainly.com now for free help!
amistre64
  • amistre64
lets find the cos of x..... think we can?
amistre64
  • amistre64
cos(2x) = cos(x)cos(x) - sin(x)sin(x)
amistre64
  • amistre64
sin^2(x) + cos^2(x) = 1 cos^2(x) = 1 - (-1/4)^2 cos^2(x) = 1 -1/16 cos^2(x) = 15/16 cos(x) = sqrt(15)/4

Looking for something else?

Not the answer you are looking for? Search for more explanations.

More answers

amistre64
  • amistre64
cos(2x) = sqrt(15)sqrt(15) -1(-1) ------------- - -------- 4(4) 4(4)
amistre64
  • amistre64
cos(2x) = 15 - 1 ------ 16 cos(2x) = 14/16 = 7/8
anonymous
  • anonymous
oh my gosh, that makes total sense now! i just have trouble picking what identity or formula to use.
amistre64
  • amistre64
trig is 90% memorizing
anonymous
  • anonymous
yeahh, tell me about it. but thank you!
amistre64
  • amistre64
the only time your gonna have to actually worry about this stuff is in calculus classes when you try to manipulate formula into derivatives and integrals.... other than that....pointless. A calculator gives you all the answers
anonymous
  • anonymous
ohh gotcha. but why do you use cos2x= cosxcosx - sinxsinx? i thought that was a sum and difference formula? im just a little confused with that part.
amistre64
  • amistre64
since they want you to find cos(2x) and give you sin(x) its only natural :)
anonymous
  • anonymous
oh, okay got it!

Looking for something else?

Not the answer you are looking for? Search for more explanations.