There comes a Integral !

Calculus Level 2

$\large \displaystyle \int_{1}^4 (5x^2-8x+5)\, dx = \, ?$

1 solution

Samara Simha Reddy
Apr 10, 2016

$\large \displaystyle \int_1^4 (5x^2 - 8 x + 5) dx = \left[\frac{5 x^3}{3} - \frac{8 x^2}{2} + 5 x \right]_1^4$

$\large \implies \left[\frac{5x^3}{3} - 4x^2 + 5x \right]_1^4$

$\large = \frac{320}{3} - 64 +20 - (\frac{5}{3} - 4 + 5)$

$\large = \frac{320}{5} - \frac{5}{3} - 64 - 5 + 20 + 4$

$\large = \frac{315}{5} - 69 + 24$

$\large = 105 - 45 = \boxed{60}$ .

You beat me in the solution by 3 minutes!

A Former Brilliant Member - 5 years, 2 months ago

But I am not that much smart as you are sir. ;)

Samara Simha Reddy - 5 years, 2 months ago

Please don't call me sir. I am 3 years younger than you sir so you are definitely smarter than me. ;)

A Former Brilliant Member - 5 years, 2 months ago

@A Former Brilliant Member – Respect is independent on Age ;)

Samara Simha Reddy - 5 years, 2 months ago

@Samara Simha Reddy – I took 30 sec for this

Syed Baqir - 5 years, 2 months ago

@Syed Baqir – For uploading question??

Samara Simha Reddy - 5 years, 2 months ago

@Samara Simha Reddy – for solving it ! :D

Syed Baqir - 5 years, 2 months ago

@Syed Baqir – Oh. Same here. But took time to type solution using latex ;)

Samara Simha Reddy - 5 years, 2 months ago

@Samara Simha Reddy – I am using this website almost half year later (when I stopped) and I forget how to use LATEX but anyway nice job :D

Syed Baqir - 5 years, 2 months ago

Were quite the same action

A Former Brilliant Member - 5 years, 1 month ago