Answer:
9p^2q-5pq^2-pq+5q^2
Step-by-step explanation:
Tan(x)= sin(x)/cos(x), therefore, substitute sin(x)/cos(x) in the expression:
=(cos(x)(sin(x)/cos(x))-1)/cos^2(x)
simplify the 2 cos(x):
=(sin(x)-1)/cos^2(x)
Sin^2(x)+ cos^2(x)=1, sin^2(x)-1=- cos^2(x), substitute in the expression:
= -cos^2(x)/cos^2(x)= -1
A^2 + B^2 = C^2
6^2 + B^2 = 7^2
36 + B^2 = 49
B^2 = 13
B = 3.61
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To find the value of x let's make the situation a bit easier
3x+10+70=180
3x+80=180
3x=180-80
3x=100
x = about 33.33
Answer:
Distance between the surface and source of light will be increased by 6 meters.
Step-by-step explanation:
The illuminance of a surface varies inversely with the square of ts distance from the light source.
Let illuminance of the surface = x lumens per square meter
and distance from a light source = y meter.
Now x ∝ 
Or
[k = proportionality constant]
Now we will find the value of k.
k = xy²
k = 120×(6)²
k = 4320
We have to calculate the distance of the source if illuminance of the surface is 30 lumens per square meter.

y² = 
y² = 144
y = √144 = 12 meters
So the source of the light will be shifted away from the surface = 12 - 6 = 6 meters.