2017年10月5日 · 1/8. cos20^@cos40^@cos80^@, =1/(2sin20^@)(2sin20^@cos20^@)cos40^@cos80^@, =1/(2sin20^@)sin(2xx20^@)cos40^@cos80^@, =1/(4sin20^@)(2sin40^@cos40^@)cos80^@, …

2020年6月15日 · Our results of cos80° have been rounded to five decimal places. If you want cosine 80° with higher accuracy, then use the calculator below; our tool displays ten decimal places. To calculate cos 80 degrees insert the angle 80 in the field labelled °, but if you want to calculate cos 80 in radians, then you have to press the swap unit button ...

2018年4月21日 · #cos80^@-cos40^@+sqrt3cos70^@=?# #cosA-cosB=-2sin((A+B)/2)sin((A-B)/2)# #cos80^@-cos40^@=-2sin((80^@+40^@)/2)sin((80^@-40^@)/2)=-2sin60^@sin20^@=-2(sqrt3)/2sin20 ...

2018年7月26日 · #(2((cos80^0+isin80^0))^3=2^3(cos80^0+isin80^0)^3# By De-Moivre's theorem; #(cosA+isinA)^n=cosnA+isinnA# #=8(cos(3xx80^0)+isin(3xx80^0))#

2017年10月8日 · #cos80+cos40-cos20=cos20-cos20=0# #QED# Answer link. Related questions.

2017年5月15日 · cos100cos120cos140cos160 =cos(180-80)cos(180-60)cos(180-40)cos(180-20) =(-cos80)(-cos60)(-cos40)(-cos20) =cos20xxcos40xxcos80cos60 =1/(8sin20)xx4 ...

Answer: hai . Step-by-step explanation: this is the answer for your question

2016年9月10日 · How do you perform the operation in trigonometric form #(2(cos120+isin120))/(4(cos40+isin40))#?

2021年7月1日 · Find an answer to your question Topic :- Trigonometry1) Value of 'cos20° + cos80° - √3.cos50°'.2) Value of 'cos0° + cosπ/7 + cos2π/7 + cos3π/7 + cos4π/7 + cos5π… sharanyalanka7 sharanyalanka7

2019年2月17日 · Step-by-step explanation: Given : Expression To find : What are the steps to expression ? Solution : Using trigonometric properties,