Find \int_0^{\frac{π}{2}} \,5 \,sinx \,dx.

(a) -5

(b) 9

(c) 5

(d) -9

I have been asked this question during an online interview.

The above asked question is from Fundamental Theorem of Calculus-1 topic in chapter Integrals of Mathematics – Class 12

NCERT Solutions for Subject Clas 12 Math Select the correct answer from above options

Interview Questions and Answers, Database Interview Questions and Answers for Freshers and Experience

The correct answer is (c) 5

The best explanation: Let I=\int_0^{\frac{π}{2}} \,5 \,sinx \,dx

F(x)=\int5 \,sinx \,dx=-5 \,cosx

Applying the limits by using the fundamental theorem of calculus, we get

I=F(\frac{π}{2})-F(0)

∴\int_0^{\frac{π}{2}} \,5 \,sinx \,dx=-5[cos\frac{π}{2}-cos0]

=-5[0-1]=5