Question

Find the value of by first Principle rule -

• A. cos a – cos b
• B. sin a – sin b
• C. cos b – cos a
• D. sin b – sin a

Answer 1

Answer: (A)

cos a – cos b

Answer 2

Here ƒ(x) = sin x & nh = b – a from the definition,

$\int _ { a } ^ { b } \sin x$ dx = h

= h {sin a + sin (a + h) + sin (a + 2h)

+ … + … + sin (a + n – 1h)}

= h

= h

=

= 2 . 1 . sin sin

= cos a – cos b.