Ah okay so in differential equations you usually want the top variable isolated. To do this, multiply by dt and 2u and you get

Now just integrate both sides. The integral of 2u with respect to u is u². The integral of (2t + sec²(t) with respect to t is t² + ∫sec²(t)dt. The last part is just tan(x) because d/dt(tan(t)) is sec²(t) so just integrating gets us back. Now we have

Where c and k are arbitrary constants. Subtracting c from k and you get

Where b is another constant. To find b, just plug in u(0) = -1 where u is -1 and t is 0. This becomes

tan(0) is 0 so b = 1. Take the plus or minus square root on both sides and you finally get

But Brainly didn't let me do but juat remember there is a plus or minus square root on the left.
Answer:
A. -24
Step-by-step explanation:
we know that
A relationship between two variables, x, and y, represent a directly or proportional variation if it can be expressed in the form
or 
In this problem we have
For x=-3, y=12
Find the value of the constant of proportionality k

substitute the given values

so
The linear equation is equal to

what is the value of y when x=6?
substitute the value of x in the linear equation and solve for y

B because the amount of toys you have and calories you eat do not depend on one another
Step-by-step explanation:
5 gallons 3 quarts +4 gallons 2 quarts
5.3
+
4.2
=9.5 gallons
AB (y=3) and CD (y=6) are parallel, but different lengths. The figure is a trapezoid. A diagram shows it to be an isosceles trapezoid.