If a is an acute angle, then the minimum value of 1 / 2 of sina plus 4 / 2 of cosa is? Dear friends, please be more serious. Four people answered three kinds of answers. It's a test of my IQ~

1 / 2 of sina plus 4 / 2 of cosa > = 2 * (root sign (4 / (sin ^ 2A * cos ^ 2a)))
= 8 / sin(2a) >= 8

Find the maximum, minimum and period of y = (Sina COSA) ^ 2

y=(sina-cosa)²
=sin²a+cos²a-2sinacosa
=1-sin2a
That is y = 1-sin2a
So the maximum is 2 and the minimum is 0
The period is 2 π / 2 = π

Y = Sina + cosa Sina * cosa, find the maximum and minimum value, the value range of a?

（sinA+cosA）^2=1+2sinA*cosA
sinA*cosA=[（sinA+cosA）^2-1]/2
Let Sina + cosa = t, t range [- radical 2, radical 2]
sinA*cosA=（t^2-1)/2
y=t-（t^2-1)/2
The rest is OK, the function is the maximum, a belongs to R

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