can anyone please help me with these problems
1) cos20*cos40*cos80=1/8
2) sina+sin3a+sin5a/cosa+cos3a+cos5a=tan3a
2006-09-23 17:29:45 · 3 answers · asked by Anonymous in Education & Reference ➔ Homework Help
Type in the cosine of 20 on your calculator... then multiply it by the cos 40... etc. You already have it equal to something so what are you trying to solve or do?
2006-09-23 17:37:48 · answer #1 · answered by Anonymous · 0⤊ 1⤋
What do you need help with? Your question is very vague. If you are getting the wrong answer on these make sure your calculator is in the right mode (radian or degree)
cos function is eqaul to a/h
sin function is equal to o/h
tan funtion is equal to o/a
1) (should be in degree mode it seems) Believe it or not comes out to the decimal .125 which is 1/8
2) Whats the whole equation?
2006-09-24 00:46:16 · answer #2 · answered by TheTechKid 3 · 0⤊ 0⤋
cos(a+b)=cos a . cos b - sin a .sin b
cos(a-b)=cos a. cos b + sin a .sin b
add them
cos a. cos b= 1/2 [cos(a+b)+cos(a-b)]
Use this formula for the first question.
The second question is not complete.
2006-09-24 00:50:34 · answer #3 · answered by iyiogrenci 6 · 0⤊ 0⤋