MaxWong

7/8 = 0.875

1/4 = 0.25

7/8 - 1/4

= 0.875 - 0.25

= 0.625

Our guest 1 minute is not 6 degrees......

1 degree = 60 minutes

1 minute = 60 seconds....

Btw you can't type angles in with degrees minutes and seconds. You type it as degrees.

Example:

72°30'12''

= 72° + 30/60 ° + 12/3600 °

= $\frac{21751°}{300}$

$(a-b)^3 = a^3-3a^2b+3ab^2-b^3$

Therefore$(r-5)^3=r^3-(3)(r^2)(5)+(3)(r)(5^2)-5^3=r^3-15r^2+75r-125$

25 - 7 x 2 + 5 ÷ 5 = 12

-(1000000000000000000000000000000000000000000000101001010100100101001-17)

= -1000000000000000000000000000000000000000000000101001010100100100984

$15\frac{6}{16}\div3 = (15\div3)+(\frac{6\div3}{16})= 5\frac{2}{16}= 5\frac{1}{8}$

Ans- $\frac{1}{2}=5\frac{1}{8}-\frac{1}{2}= 5\frac{1}{8}-\frac{4}{8}= \frac{41-4}{8}=\frac{37}{8}= 4\frac{5}{8}$

I am not very good at trig but I will try to solve it.

$(cos\space x-5sin\space x)^2=Acos\space 2x+Bsin\space 2x+C$

$cos^2\space x - 10sin\space x\space cos\space x + 25sin^2\space x= A(cos^2\space x - sin^2\space x)+B(2 sin\space x\space cos\space x)+C$

The form of left hand side doesn't fit in the form of right hand side......

2x and 3x are like terms.

but 2x and 3y aren't

It means 'of the same variable' .

But note that 2x and 3xy aren't like terms too. The part without coefficient(for 2x the coefficient is 2, and for 3xy the coefficient is 3) should be EXACTLY the same.

$cos30 = \dfrac{adjacent \space side}{20}$

$adjacent \space side = 20 cos30 = 10\sqrt3$

$opposite \space side=\sqrt{20^2-(10\sqrt3)^2}=\sqrt{100}=10$

$atan(\dfrac{10\sqrt3}{10})= atan(\sqrt3)=60 \space degrees$

Wait, if that is for right-angled triangles why I don't just 90 - 30 ...... never mind, at least I got the answer XD