superb ques

Let
f(x)=(x2+4x)1/3

and let g(x) be an antiderivative of f(x). Then if

g(5) = 7

find

g(1)

12 Answers

39
Pritish Chakraborty ·

Non-integrable function...it should be square root power.

1
1.618 ·

Whats there in the power of f(x)?

Not clear.

39
Pritish Chakraborty ·

It's a cube root Ray. It can't be integrated. I don't think you've done integral calculus as yet...the "anti-derivative" is also known as the integral.

1
Techboy ·

power is 1/3

1
1.618 ·

I am doing calculus...know the basics.

39
Pritish Chakraborty ·

Superb question hai srk...solve hi nahi kiya jaa sakta(unless you are Gallardo, Anant sir, or the like). Next time give us an integrable function, okay? [1]

1
Techboy ·

well pritish u need to reshuffle ur calculus.anyhow here's solution
Since g(x) is an antiderivative of f(x), we have

g '(x) = f(x)

or g(x)=∫(t2+4t)1/3dt,taking limits L-a and U-x

None of the regular techniques of integration will work on this integral. Even the computer cannot solve this explicitly. Instead of integrating, we let

h(x) = g(x) - 7

Then h(x) is also an antiderivative of f(x) and

h(5) = 0

We can write
h(x)=∫(t2+4t)1/3dt,take limits L-5,U-x

Notice that when we plug in 5 for x, we get 0 as required, since the upper and lower limits are equal. Now use a calculator to easily find
h(1)=)=∫(t2+4t)1/3dt=-10.88222 take limits l-5,u-1

finally since

h(x) = g(x) - 7

it follows that

g(x) = h(x) + 7

and that

g(1) = h(1) + 7 = -10.88222 + 7 = -3.88222

39
Pritish Chakraborty ·

"Now use a calculator to easily find.."
lol calculator kaun dega tujhe exam mein?

1
1.618 ·

@ srk bhai..wait toh karte..i was trying!![3][1]

Still, good one. But are we allowed a calculator?

39
Pritish Chakraborty ·

srk..do you understand your own solution? Bas itna bata do. [1]

1
Techboy ·

are pagal this question is just for knowledge.paagal hai tu .

1
Techboy ·

pritish naha ke aa jaa aur kaan aur aankh dho le.heeeeeeeeeeeeeeee

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