1.Let f(x)={ln(cosx)ax,x>00,x=0ex−1bx,x<0f(x)=\begin{cases} \frac{\ln(\cos x)}{a x}, & x>0 \\ 0, & x=0 \\ \frac{e^x-1}{b x}, & x<0 \end{cases}f(x)=⎩⎨⎧axln(cosx),0,bxex−1,x>0x=0x<0. If f′(0)=π4f'(0)=\frac{\pi}{4}f′(0)=4π, thena.a+b=2a+b=2a+b=2b.b−a=2b-a=2b−a=2c.a+b=−2a+b=-2a+b=−2d.b−a=4b-a=4b−a=4Login to continueOnly logged in users canattempt or see the solution.