$If($:$a_1,a_2,a_3$:$)is$ the unit tangent vector $in$ the direction $oft$ increasing for

vec$(r)(t)=($:$e^{t}cos(t),e^{t}sin(t),\sqrt[\phantom{2}]{2}{e}^t$:$)att=0$

Write $a_1,$ rounded $to$ two digits after the decimal sign.