We are given with the rate of change of the base, db/dt equal to 1 ft/ sec and the rate of change of the height of the triangle, dh/dt equal to 2 ft/sec. b is 10 ft and h is 70 ft. Area of triangle is equal to A= 0.5 bh The rate of change of the area is equal to dA/dt = 0.5 b dh/dt + 0.5 h db/dt. Substituting, dA= 0.5*10*2 + 0.5*70 * 1 equal to 45 ft2 / sec.
It should be D, I did the math :)
Answer:
Step-by-step explanation:
You can start by recognizing 19/12π = π +7/12π, so the desired sine is ...
sin(19/12π) = -sin(7/12π) = -(sin(3/12π +4/12π)) = -sin(π/4 +π/3)
-sin(π/4 +π/3) = -sin(π/4)cos(π/3) -cos(π/4)sin(π/3)
Of course, you know that ...
sin(π/4) = cos(π/4) = (√2)/2
cos(π/3) = 1/2
sin(π/3) = (√3)/2
So, the desired value is ...
sin(19π/12) = -(√2)/2×1/2 -(√2)/2×(√3/2) = -(√2)/4×(1 +√3)
Comparing this form to the desired answer form, we see ...
A = 2
B = 3
Answer:
D. 
Step-by-step explanation:
Area of rectangle = 
Length of rectangle = (x - 8)
Width = (x + 11)
Area of rectangle = 
Expand the expression
(distributive property of multiplication)
Combine like terms
Expression for the area of the rectangle =
You can do that using +6 and -6 .
(6) · (-6) = - 36
(6) + (-6) = 0
