Question 606372
1.Interval 0 is less than or equal to x which is less than or equal to 2pie. Solution of cos squaredx = cos x
For 0 < x < 2&#960;
cos^2x=cosx
cos^2x-cosx=0
cosx(cosx-1)=0
cosx=0
x=&#960;/2 and 3&#960;/2
..
cosx-1=0
cosx=1
x=0
ans:
x=0, &#960;/2, and 3&#960;/2
 
2. Express as a single fraction,the exact value of sin 75°
I assume you mean sin 75º
Using sin addition formula:
sin 75=sin(30+45)
=sin30cos45+cos30sin45
=1/2*&#8730;2/2+&#8730;3/2*&#8730;2/2
=&#8730;2/4+&#8730;6/4
=(&#8730;2+&#8730;6)/4