What is Sin(pi/2) and Tan(3pi/4)?

Answer 1

the arguments in them are radians

pi radians = 180 degrees
so pi/2 = 90 degrees
3pi/4 = 135 degrees = 90 + 45 degrees

sin (pi/2) =1
tan (3pi/4) = tan (pi - pi/4)
= sin (pi-pi/4) / cos(pi-pi/4)
= sin(pi/4) / (-cos(pi/4) )
= -1

Answer 2

Remember that there are 2pi radians in a circle.
Starting at the 3 o'clock position are going 90 degrees counterclockwise you get to the 12 o'clock position or pi/2. Sin is the vertical line divided by the radius. In this case they are the same, so sin(pi/2) =1

Next continuing clockwise rotate the raduiu to the 10:30 position , or at a 45% angle in the upper left quadrant. This is 3/4pi.
The vertical line from the x=axis to the point on the circle is the same length as the distance from the point on the x=axis to the origin. The x-distance is negative because it is to the left of the origin,
so tan(3/4 pi) is -1
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Answer 3

Sin (pi/2) =1

Tan (3pi/4)= - 1

Answer 4

sin (pi/2) = 1
tan (3pi/4) = -1

Answer 5

sin(pi/2)=sin(90)=1

tan(3pi/4)=tan(135)=-1

Answer 6

sin (π / 2) = 1
tan (3 π / 4) = - 1 (2nd. quadrant)