Answer:
Step-by-step explanation:
sin(180°-∅)=sin∅ as its in the 2nd quadrant
then tan(180°-∅)= -tan∅ as its in the 2nd quadrant and there only sin and cosec is positive and at last cos(180°-∅) = -cos∅ for the same reason
so by putting the values:
sin∅/sin∅ + -tan∅/tan∅ + -cos∅/cos∅ =1-1-1= -1
thanks ..
Height of the wall is 27 m.
<u>Explanation:</u>
Let the height of the wall = h
Length of the ladder = 9 m
Angle of elevation = 60°
Ladder rests at 9 m below a vertical wall.
So, length of the wall upto which the ladder rests = h - 9
We know,
Cos Ф = base/ hypotenuse
cos 60° = length of the ladder / height of wall upto which the ladder rests

So,
h - 9 = 18
h = 27
Therefore, height of the wall is 27 m