1.

If `f(x)=0`is a quadratic equation such that `f(-pi)=f(pi)=0`and `f(pi/2)=-(3pi^2)/4,`then `("lim")_(xvecpi)(f(x))/("sin"(sinx)`is equal to0 (b) `pi`(c)`2pi`(d)none of these

Answer» Correct Answer - C
It is given that `f(-pi)=f(pi)=0`. Therefore ,`-pi` and `pi` are zeroes of `f(x)`.
`therefore f(x)=a(x+pi)(x-pi),a ne 0`
` rArr f((pi)/(2))=-(3api^2)/(4)rArr(-3pi^2)/(4)=-(3api^2)/(4)rArr a=1`
`therefore f(x)=(x+pi)(x-pi)`
So, `lim_(xto-pi) (f(x))/(sin(sinx))`
`=lim_(xto-pi)((x-pi)(x+pi))/((sin(sinx))/(sinx)xx sinx )=-lim_(xto-pi)((x-pi))/((sin(sinx))/(sinx))xx((x+pi))/(sin(pi+x))=-((-pi-pi))/(1)xx1=2pi`


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