A/ 0 SIN2X 1 , ∀ X R B/ 0 COS2X 1 , ∀ X R C/ –1 SINX 0 , ∀ X [– Π2 ; 0] D/ –1 COSX 0 , ∀ X [– Π2 ; 0]

câu 7: - LUYEN THI TRAC NGHIEM LUONG GIAC câu 7: - LUYEN THI TRAC NGHIEM LUONG GIAC
Lớp 11 Toán LUYEN THI TRAC NGHIEM LUONG GIAC

Câu 7: Chọn câu sai:

a/ 0

sin

2

x

1 ,

∀

x

R

b/ 0

cos

2

x

1 ,

∀

x

R

c/ –1

sinx

0 ,

∀

x

[–

π

2

; 0]

d/ –1

cosx

0 ,

∀

x

[–

π

2

; 0]