2018年4月1日 · cos^2pi=1 cos^2pi=(cospi)^2=(-1)^2=1. ... What is the value of cos^2 pi? Trigonometry. 1 Answer Monzur R. ...

2015年10月2日 · You get cos(2pi)=1 The easiest way (at least for me) it is "to see" its value using the unit circle and the meaning of cos in terms of the "length"of it. Consider a circle of radius 1 …

2016年9月30日 · Use the known trigonometric identity . #cos(a+b)=cosa*cosb-sina*sinb# we have that. #cos(x+pi/2)=cosx*cos(pi/2)-sinx*sin(pi/2)=cosx*0-sinx*1=-sinx#

2018年3月15日 · We know that ,cos is an even function. #=>cos(-theta)=costheta# #:.cos(x-pi/2)=cos(pi/2-x)=sinx# OR #cos(A-B)=cosAcosB+sinAsinB#

2016年3月31日 · Since this is a proof, we do not have a short answer. See the explanation below.

Using the double angle formula, how do you find the function values for #cos^2(pi/12) and sin^2(pi/8)#? How do you find the exact value of the expression sin 2x, cos 2x, and tan 2x …

2016年4月30日 · LHS #=cos^2(pi/7)+cos^2(2pi/7)+cos^2(4pi/7)# using formula #cos^2theta=1/2(1+cos2theta)# #=1/2(1+cos(2pi/7))+1/2(1+cos(4pi/7))+ 1/2(1+cos(8pi/7))#

2017年3月4日 · =sinxtanx Since cos(pi/2-alpha)=sinalpha, you get sin^2x/cosx =sinxtanx

2017年1月11日 · cos(x+(3pi)/2) = sinx Using the expression for the cosine of a sum of angles: cos (alpha + beta) = cos ...

2016年5月1日 · This is a well used trig. relation along with #sin(pi/2-theta)#. that is : #cos(pi/2-theta)=sintheta" and " sin(pi/2-theta)=costheta#