I dont understand the min and max Find the smallest positive

I don\'t understand the min and max

Find the smallest positive value of t for which f(t) = 5 sin (t - pi/4). is the following. f(t) is zero. f(t)- attains a maximum. f(t) attains a minimum value.

Solution

we know that sine function attains maximum at pi/2 for first time and minimum at pifor first time.

so, argument is x- pi/4

for maximunum x-pi/4 = pi/2

x = 3pi/4

for minimum, x-pi/4 = pi

x = 5pi/4

zero when x-pi/4 = 0

x = pi/4