Find the value of cos(5π4)cos(−π4)sin(3π4)cos(3π4)
cos(π+π4).cos(−π4)sin(π−π4).cos(π2+π4)
= −cosπ4×cosπ4sinπ4(−sinπ4)
= cot2π4
= (1)2
= 1
cosπ7. cos3π7. cos5π7 are the roots of the equation 8x3−4x2−4x+1=0. Then the value of sinπ14.sin3π14.sin5π14 is
If 5tanθ=4, then value of (5sinθ -4cosθ)/(5sinθ +4cosθ) is: