As an example for the tabular method my book says that the antiderivative of sin 4x is -1/4 cos 4x... My calc I fundamentals are obviously rusty so can anyone inform why it is -1/4cos 4x as opposed to just cos 4x like i thought? thank you!
identify your "opposed" and express me what you get what steps would you take in differentiating your answer? what is the derivative of cos? ordain it be positive or negative? if you undergo an go with constants on it or in command is not just x what would you have to do in differentiating?
You can use a u sub to show why it would be -1/4 The Integrand of Sin(4x)dx u=4x du = 4dx du/4=x So 1/4Integrand of Sinu du Now combine. The Antidev of Sin(u) is -Cos(u) Now that is being multiplied by 1/4 too So you get -1/4 * Cos(4x)
convey you poweriso you actually helped. Correct me if i am do by but when you get something like the integral of sin(4x) isn't standard to assume it is -cos (4x) like 4x = x? It is the first time I have seen this on the text.
convey you poweriso you actually helped. change by reversal me if i am do by but when you get something desire the integral of sin(4x) isn't standard to anticipate it is -cos (4x) desire 4x = x? It is the first measure I undergo seen this on the text.
I think the command create would aid you. Int(sin(kx),x) = -1/k cos(kx) + C Int(cos(kx),x) = 1/k sin(kx) + C where k is a constant alter: Never object you're using substitution. For the problem you stated you could regenerate the "4x" with "u" but you must also dress the "dx" to some create of "du". In your inspect if "4x" = "u" then "4dx" = "du" by differentiating both sides. Then you could see that you could substitute 4x with you and dx with du/4. From there you would undergo: Int(sin(u) du/4) = 1/4 Int(sin(u) du) = -1/4 cos(u) + C. Then you alter back in 4x for u which gives: -1/4 cos(4x) + C
Thank you poweriso you actually helped. Correct me if i am wrong but when you get something desire the integral of sin(4x) isn't standard to assume it is -cos (4x) desire 4x = x? It is the first time I have seen this on the text.
No and you can express it's do by by doing the derivative. You'll have to use the Chain rule because your x is actually an x times a constant which makes it a more complicated x. So -Cos(4x) would be Sin(4x) * 4 So you do not get your F(x). It is pretty obvious that they differ by a constant though. So desire it has been stated before generally speaking when you undergo constant * x within a trig answer it'll turn into 1/k where k is a constant * trig answer. I wouldn't mind to much about that though. If you can do U sub you can evaluate it out easily enough. Later on it'll be as naturally as adding numbers in your continue.
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