Answer:
sec(4x) + C
Explanation:
original problem: ∫sec(4x)tan(x)dx
use integration by substitution (u-sub) by setting u = 4x
if u = 4x, then du/dx = 4 and du = 4dx (dx = du/4)
after substitution the integral is ∫sec(u)tan(u)(du/4)
move the 1/4 out of the integral by using the integral Constant rule to form 1/4∫sec(u)tan(u)du
the anti-derivative of sec(u)tan(u) is sec(u), memorize your trigonometric derivatives!!!!
after integration, we get sec(u)/4 + C , now plug u back into the equation
sec(4x) + C is the general solution
The following are some of the reasons we preserve our food.
Not to lose it freshness
.To prevent contamination and infection
.To prevent food from smelling
.To keep insect and other pest away from the food.
Keeps farm produce in good condition for planting in the next season
.To keep food for a long period of time.
Answer:
D. desire to surprise his friend and his friend’s failure to recognize him
Explanation:
Answer D
Correct. In these sentences, the author presents a humorous reversal that emerges from the ironic incongruity between the traveler’s plan to “overpower” his old friend with an excess of pleasure and the anticlimactic outcome of the surprise visit. As it turns out, the friend experiences no immediate pleasure from the visit because he fails to recognize the traveler and can only be made to remember him after the traveler gives a “gradual (in this context, methodical) explanation” of who he is.
Color imagery helps the reader make connections with things in their everyday life and gives a stronger visualization.
