Post a New Question

trig

posted by .

can someone please help me with this problem. i'm doing my review right now and i'm stuck?

Find cos(s + t) given that cos s = 1/3, with s in quadrant 1, and sin t = -1/2, with t in quadrant 4.

  • trig -

    s in I
    if cos s = 1/3, then sin s = √8/3

    t in IV
    if sin t = -1/2, then cos t = √3/2

    cos(s+t)
    = cosscost - sinssint
    = (1/3)(√3/2) - (√8/3)(-1/2)
    =(√3 + √8)/6

  • trig -

    this is the wrong answer..

  • trig -

    I am 100% sure my answer is right.

    What have they got?
    Is is (√3 + 2√2)/6 perhaps.

    If it is, I will let you think about it.

  • trig -

    yes, (√3 + 2√2)/6 is the correct answer/form. thank you for your help!

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

More Related Questions

Post a New Question