Ta có: $sin^{10}x\leq sin^2x$ $cos^{11}x\leq cos^2x$$\Rightarrow sin^{10}x+cos^{11}x\leq sin^2x+cos^2x=1(dpcm)$
hình như là áp dụng cái này:+)$sin^kx\leq sin^2x (k\geq 2)$+)$cos^kx\leq cos^2x (k\geq 2) $Ta có: $sin^{10}x\leq sin^2x$ $cos^{11}x\leq cos^2x$$\Rightarrow sin^{10}x+cos^{11}x\leq sin^2x+cos^2x=1(dpcm)$
Ta có: $sin^{10}x\leq sin^2x$ $cos^{11}x\leq cos^2x$$\Rightarrow sin^{10}x+cos^{11}x\leq sin^2x+cos^2x=1(dpcm)$